u just need a new gpu the rest looks good dude. u wont see an increase going from ur 2500k to a 3770k or close to it.
for best bang for bucks u want a 7970.http://www.newegg.com/Product/Product.aspx?Item=N82E16814202008&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=
if u must go with the 670 than go with this.
since the 680 isnt in ur budget.http://www.newegg.com/Product/Product.aspx?Item=N82E16814130782
either one is good, but to me the 7970 is better deal, beats a stock 680 and when overclocked is a beast.
but if u need cuda support and love nvidia the gtx 670 can overclock to 680 levels and still be great.