Morphix,
Reviewing Passmark Performance Test 8.0 baselines, it appears you'd be better off using the HD4000 graphics than the GeForce GT 210.
This system > i5 3750K + ASUS P8Z77-M + 4GB RAM + HD4000 scored >
Overall rating of 2013 >CPU= 7192 >2D= 703 > 3D= 497 > MEM= 1746 > DISK= 1064
The only system in the charts using the i5-3750K +Gigabyte Z77X-UD3H + a dedicated card comparable to the GT 210 is using a 9500 GT and scored >
Overall rating of 1315 > CPU= 7158 > 2D= 799 > 3D= 249 > MEM= 1719 > DISK= 527
As most of the parameters are quite similar, part of the difference in the rating is likely to be the disk performance, but especially if you'll be using the new computer for games, the better 3D of the HD4000 is worth the price of admission- $0! I've seen a number of results in this test where the HD4000 does better than dedicated cards.
The i5-3570K is a good performer and the high scoring ones seem to use GTX 660, 680, 580. The top rating for that CPU is 5111 using a Radeon HD 7950.
If I might suggest, as a temporary solution, if you have about $50-70- (sell the GT 210 for $20) and try for good deal on a used GTX 285 off eBay. That's a 512-bit, 240 CUDA, 1GB (there's a 2GB version too, at about $150) and even by today's standards a good performing card. Keep in mind it uses 205W. The top scoring i5-3570K + GTX 285 system >
i5-3570K+ ASUS Sabertooth + 16GB RAM + GTX 285 > Rating=3958 > CPU= 8493 > 2D= 1001 > 3D= 1465 > MEM= 2627 > DISK= 3672/ (OCZ Vertex).
If you get a great deal on the GTX 285- some sell for $40 or so, you could even buy 2 and run them in SLI- probably with surprisingly good results !
I bought a used GTX 285 (6 mo. old $140) and employed it in a Dell Precision T5400 for almost 2 years in heavy 3D CAD and 2D graphics- great performance (scored 2239) with and perfectly reliable. That way you can get respectable performance while looking around (and saving up) for a card that will be appropriate for that very good CPU, your uses, and performance expectations.
Cheers,
BambiBoom