msi k9n6pgm2 help needed!!

[warlicrox1394]

i hav a entry lvl gaming desktop
specs as follows
AMD Phenom Quad Core 9550
corsair ddr2 ram 2gb 667 mhz
msi k9n6pgm2-motherboard
nvidia geforce 8400 gs

here r my probs
i want 4 gigs of ram (2x2 gb preferably corsair 667 mhz)
and wud like to kno the cost and availability in india

i also wanted to know if my motherboard wud support sapphire radeon hd5750 1gb

10x in advance