I am bulding a new gaming pc but with limited budget and i was wondering what card to buy?

spec:
-LC8650 "Ozeanos" v2.2 650W
-ASUS p5q pro
-intel E8500 3166 Mhz
-4bg 2x2GB 1066 Mhz dual channel
-640GB 32mb disk

so i was wondering what graphic card to get with this system
2x 4770 512 DDR5 or 4890 1gb

i will be running games on a 1650x1050 resolution

i was also thinking to get 2x 4770 and then when i get bigger budget sell these and get 2x 4890.

i didnt give much tought on geforce series so if annyone could shed some light on the matter?

oh and 4890 is about 10 more expensive.