I would personally recommend this for your price range
http://www.digitaltigers.com/stratosphere-pro-z6.asp
for gaming it will absolutely destroy the mac you currently have, and it'll probably run teamspeak too
Specs-
- 64-Bit windows 7 professional w/ XP mode (you do not want windows 8)
- Intel Core i7-4770, Quad core, clocks at 3.4-3.9 Gh/z w/ turbo boost (4th gen)
- Standard build supports 6 monitors (DVI ports), however i'd recommend only running two at 2560*1600 resolution
- Dual Nvida Geforce 600 keplar graphics cards
- Standard build comes with 8GB RAM, standard motherboard supports 32gb, upgrading the motherboard can allow you to install 64gb ram
- 128GB SSD
- 10x USB ports (6 USB 3.0, 4 USB 2.0)
- 8 channel digital surround audio
Basically it's pretty good, imo at least, however if you can get some extra money together for it then go to the customize section, and upgrade the RAM and CPU