I installed one of these in my office (similar to yours, all the computer gear means it's the hottest room in the house):
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Needs to be close enough to an outlet, but it really pulls a lot more cold air from the vent than I got with just a low restriction vent. Has taken care of the hotter temps in the office.