Game suggestions?

So, I am looking for some games I may enjoy, however since I am on a mac 2011 mini with relatively limited power, it is difficult. And before you ask, I cannot dual-boot or get a windows… My dad does not want that kind of vulnerability on our network.

Anyway, back on topic, my favorite games are the half life and counter-strike games, garry’s mod, modded minecraft, rust, (When there are no sleepers), Infamous Second Son, Civ V, and the halo series.

Specs:
Processor: 2GHz Intel Core i7
RAM: 8 GB 1333 MHz DDR3
Graphics: Intel HD Graphics 3000 512 MB
OS: OS X 10.9.2 (Mavericks)

(As you can see, not exactly a gaming rig)

Any suggestions would be appreciated.
Thanks,
lilshatespug217

Damm that videocard…

Yeah… It’s a little sad…

512mb is to little for almost every game…a new card from 2gb is not expensive…just 50 euros (same price as a game)

@Aswin_Vos
Meh, It suits my purposes… I just need it to run source/ old games… I mean, I can run CS:GO at 30 fps, so I am happy.
But, upgradeing it is not gonna happen. If you have any experience with mac minis, there biggest problem is that you CANT FREAKING UPGRADE them.

I am saving up to build my own steamOS machine, though, so hopefully that will help with the graphics.

Speaking of which, can anyone recommend a gaming pc setup for… say… 900 Dollars? (658.8891 Euros, 532.872 Pounds)

Speaking of steamOS, @PatrickKlug, will GDT and other Greenheart projects support it?