@Olivia Collins52GB is plenty if you're running resolutions higher than Full HD (1920x1080) or driving multiple monitors from a single card. Since you're sitting at 1600x1200, you honestly wouldn't notice any difference between 1GB and 2GB.
All of these use DDR5; as far as I know, there isn't even a DDR3 version of this card available (and obviously, DDR5 is much faster than DDR3).
The cheapest GTX 650 Ti option is here:
EDIT
It's actually on sale at this link:
But this one is actually even better—it's an MSI model, so you get a year more warranty than the others, plus it's overclocked.
Then there's the Gigabyte OC version:
The last two options are from slightly more prestigious manufacturers and come factory overclocked. Even with shipping, they should only run you about $40.--$17