upgrading Ram on your sony vaio is quite easy.. i had done it for a friend.. theres nothing too complicated. just get the appropriate screw driver to open the ram slot cover beneath your laptop. (you will find decent screw driver sets for about Rs. 140 with all kinds of sizes and shapes that you will possibly need to strip down your laptop fully). all you gotta do is open the lid, see what ram you've got installed (you can take the existing ram stick with you to the market and just show it to the vendor) buy the same thing in the market (brand is not an issue, but its better if other technical specs are similar). just slide the ram stick into the empty slot. close the lid. start your pc.. and you're done. .in any windows after xp, you need not do any other manual config settings for windows to be able to see and start using the extra ram.
and yeah, now that you've got a 64 bit OS, you could definitely use the extra ram provided you have that kind of application. (you sure you need ram to make your pc faster, it might also be something else. be sure to make sure about that.)
if you're not a performance freak or anything, just need a basic 2 gb ram upgrade, u can buy a kingston, transcend etc. otherwise go for corsair...
PS: while you're doing all this, make sure you've removed the battery