Cheval_Blanc

For 610m, the in-game graphic setting is suggested to set "low", assuming you might want to have a smoothly environment
You may also try "medium" as well, to see whether the performance is acceptable or not

The following website give you the comparison of setting and ranking among various notebook-graphic cards, you can select the ideal pc game
http://www.notebookcheck.net/Computer-Games-on-Laptop-Graphic-Cards.13849.0.html

For GTA 4, the ranking of 610M is 290. Green zone represent a fair performance, while orange and red means over-burden

Cheval_Blanc

Better option will be 650M, with better performance but it might be rather costly

Cheval_Blanc

In most cases, the display card was soldered with the motherboard of the notebook, so you cannot purchase it separately. But it also depends on the model of the notebook, some of them are still replaceable. But it is rather complicated if you want to DIY, so I suggest you seek for information from retailer first.