Deep - Review this [http://support.apple.com/kb/HT1270?viewlocale=en_US&locale=en_US|MacBook Pro 13" memory guide] on what your options are and the needed specs of the memory modules you'll need.
As to your real issue you should try to figure out why your system was having problems. I still find it hard to believe your socket failed you. It's possible you zapped your memory module when you pulled it out or placed it in (ESD damage).
As to your USB & Shutdown problem I think this is related to your memory slot issue. Can you tell us if you have dropped or damaged your system in some way. Often when you have multiple problems there is a relation between them.