i have a custom built pc having an intel E5500 processor , an asus P5QPL-AM motherboard and 2 gb of ddr2 ram....i wanted to put in a graphics card in it but im concerned as to whether or not it will be supported by the hardware i already have...also if it is possible to upgrade what card should i go for.....i have two in mind both from amd..the HD7770 and the HD7750...i have a 450 watt power supply that came with the case...can anybody help me?