Q: Multiple iTunes Accounts

No you cannot but you can authorize both your accounts using one computer. Just do the steps on how to authorize your computer but for multiple accounts this time. If you need more help, contact support.

http://www.apple.com/support/itunes/

Welcome to the Apple community.

Whilst you can authorise a computer to play content from two iTunes accounts, you cannot do the same on an iOS device. If you play your music on and iOS device, you would be better sticking with one iTunes account. If you have bought a significant amount of content using your old account, then I suggest you forego any credit you have on your new one and stick with your old account.

It may not be a total loss. The iTunes stores lets you "gift" some things like apps and music. You could use the mistake account to "gift" the items to your actual account.

You might also be able to create a Gift Certificate for some of the deposited funds, that you could then deposit into the regular account.

Check out this Apple page: http://support.apple.com/kb/HT2736?viewlocale=en_US