Clarks Bros. gun shop & range in nearby Warrenton. http://www.clarkbrosguns.com/
There is a shooting range at C.F. Phelps WMA. http://www.dgif.virginia.gov/wmas/detail.asp?pid=17
But even better is that you have some great training opportunities right there in Culpeper with John Murphy of http://www.fpftraining.com/