Overtaker :
could this work https://www.amazon.com/MSI-Profile-PCI-Express-R6450-MD1GD3-LP/dp/B004X6ABTM/ref=sr_1_2?ie=UTF8&qid=1484405052&sr=8-2&keywords=graphics+card+low+profile
That thing is really bad I would suggest you a gtx 1050 / rx460 as I don't know your budget I don't know what to really look for. Also if you have a pentium D in the optilex 745 as cpu you can forget playing cs:go at all.