I suggest getting Lite-on. It comes for around rs.1900, and it's won several Best Buys.
I think you can get 512 mb ram for 1500. You've typed 1500k, so you can get anything for that money.
To install ram, take out the existing ram piece from its slot, or look how it is placed, then place the new ram stick in that slot or in the slot next to it. Then put in the 2 side-locks till you hear the click.