Before you reallocate your assets:

Review the historic returns of short-term investments, bonds, and stocks carefully over various holding periods to see if you can accept the level of risk in a given investment.
Consider the tax consequences of selling investments held outside a tax-deferred plan. For instance, you may not want to sell an investment that has appreciated significantly in value to buy another investment with a similar objective; you wouldn't have done much to alter your portfolio's risk level, but you would still be liable for the taxes on the capital gains realized from the sale.
Find out if you would incur a fee for selling an existing investment.
If you're in a high tax bracket and hold assets outside a tax-deferred plan, consider substituting tax-exempt municipal bond funds for the bond funds suggested.
If you decide to change your existing portfolio's asset allocation, you should determine how much you want to reallocate. If it's more than 10% of your portfolio, make the shift gradually, perhaps over the next few months or years.