NEW YORK (CNNMoney.com) - I've rolled money from a previous employer's 401(k) into an IRA rollover that is invested in a number of solid mutual funds. The problem is that I don't like the investment choices that are available in my current employer's 401(k) plan. So I was wondering: Couldn't I transfer money from my current 401(k) into my rollover IRA? This way I'd be able to invest in the funds I really like.

-- Mike, Coatesville, Pennsylvania

Sorry. You can roll money from your account at a previous employer's 401(k) into an IRA rollover. And you can roll money in an IRA rollover account back into your 401(k) account at a new employer, provided the company allows such transfers.

But unless you leave your job, you can't roll money from your current 401(k) into an IRA rollover.

So as far as the money you're contributing to your new 401(k) is concerned, you are pretty much stuck with the investing options offered by the plan.

That said, however, there is a way to at least make the best of the not-so-ideal situation in which you find yourself -- that is, in a plan that, from your point of view at least, has inferior investing options.

My recommendation: take the holistic approach -- that is, think of your IRA and 401(k), and any other retirement investments you own, for that matter -- as one large pie. Then consider how you want to divvy up that pie in terms of different asset classes.

You want a portion to be in stocks and some in bonds. And in the stock portion, you want slices of large and small stocks, value and growth shares. Maybe you'll also make room for smaller slivers devoted, say, to real estate-related stocks or funds or TIPS (Treasury Inflation Protected Securities) as a hedge against inflation.

How large each of these various slices or slivers should be -- the portion of the pie devoted to stocks and bonds overall and the smaller slices or slivers to particular types of stocks and bonds -- depends mostly on how long you plan to invest and your risk tolerance. But generally, the younger you are, the more you'll invest in stocks. And as you age, you'll devote more to bonds, although even well into retirement, you'll still want to own some stocks because they can help you maintain your portfolio's purchasing power.

For examples of how to divvy up your overall retirement portfolio into different types of assets, I suggest you check out "A plan for every stage", which ran as part of the investing strategy feature story in MONEY's recentDream Retirement special report. You can also get guidance on how to build your portfolio by going to the Asset Allocation tool.

Once you've decided how much of your portfolio goes into stocks and bonds and different types of stocks and bonds, you can begin choosing the specific stocks, bonds or funds to fill out those various slices of your portfolio. At that point, your goal is to get the best investments possible from the various accounts you have to work with.

Start with your 401(k) because that's where you have the least flexibility. I know you're unhappy with your choices, but there must be at least one or two that are decent. Perhaps there's a stock index fund that could work as a core holding, or maybe a small-cap stock fund or a bond portfolio that has reasonable expenses and a solid record. (It's a good idea to use your 401(k) or IRA for the bond slice of your retirement portfolio pie since the bond interest payments will remain untaxed as long as they're within the 401(k) or IRA.)

Once you've decided the role your 401(k) investments will play in your overall portfolio, move on to your IRA rollover account and any other retirement accounts you may have. In these accounts, you've got plenty of flexibility; you can choose virtually any mutual fund or stock you like. So you should have no trouble picking investments that complement those you have in the 401(k) to round out the rest of your portfolio.

So, for example, if you were able to fill the bond slice in your retirement portfolio with bond funds in your 401(k), you would create a diversified group of stocks in your IRA rollover and any other accounts.

But you get the idea. You want to create the best overall retirement portfolio you can by making the best of what's available to you in the various accounts available to you.

I'm not saying this solution will always be perfect. You could end up putting your 401(k) money in funds that are less than ideal.

But by taking this approach, you at least still get to cash in on the tax advantages and convenience of a 401(k). And if you switch jobs again down the road, well, at that point you can always roll your 401(k) money into your IRA rollover and invest it the way you like.

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