That "TC1G" is misleading, I found a card like yours click here to see it
it says TC1GB but has only 512 mb of dedicated memory. (really, who thought this brand name was a good idea should burn in hell
So, looks like you bought a 512 MB card.
Try to explain your mistake to the dealer, maybe he is kind enough to give your money back.
But still, that card is low-end regardless of its memory. It will run fine on 512 mb as more intensive stuff is simply too much for it anyway.