T-shirt model help

Right currently i’m trying to make a new personal skin with a t-shirt like This

http://s3.garrysmod.org/img/cache/7/8/7/2/7/5e8b93296afd5f1eb03018dfcbcec2cb.jpg

But the problem is i don’t know how to get a Shirt, i just end up with a civilian with a skin coulored jacket
any help?

Just download Simkas’ T-shirt guys?
http://www.facepunch.com/showthread.php?t=741913