Computer overhaul by rank amateur.

[hopmad]

I'm going to do it. I've been speaking of it for some time, but this time it's happening. I'm going to overhaul my comp. It is an HP Pavillion.
First thing I'm going to do is make a copy of the data. I've seen a WD My Passport 1TB external drive for sale at Banana IT for 2,260 baht. Is this a good buy or not?
Next I want to add 2GB of RAM to the comp. I've watched a few YouTube vids on how to do this and it doesn't look too difficult. Where should I buy the RAM?
Next I want to take off Windows XP and replace it with Windows 7. Where should I buy the program disc?
Shops in Pattaya or Rayong would be most convenient.
Any help appreciated.