You will not be better off representing yourself.I specialize in cherokee and cobb counties and i have lived in cherokee county all of my life.I will be honest and tell you 125k is not much for a 3/2 in the areas you mentioned,it can be done but you need an agent that can find the right deal.It also depends on if land is important to you or not for 125k you will not find a 1/2 or 1 acre unless it is an older home.
The land acquistition costs for the builder are so high in my area that 3/2's are going for 140 to 150 on 1/4 acre lots or less in new sundivision.1/2 acre to 1 acre homes are more in the 200 to 400k range as far as new homes go.
Go to my website at
www.gadeals.com and sign up for the free reports,there are many qualified agents that can help you out.
Part of the issue may be you are looking all over the place and need to narrow down your search those areas you mentioned besides canton and woodstock are really far apart and it's not realistic for an agent to cover an area that big,my busines oartner covers gwinnett and all of the surrounding areas.
Have you thought about paulding county?You can get a nice 3/2 on land new in your price range and the area is just rebounding in appreciation.
Just make sure you use a quality agent,it makes all the difference in the world in your stress level and your experience with the process.
good luck