Here's a link to a list of schools that offer Bachelor's degrees in Archaeology:
http://www.universities.com/On-Campus/Bachelor_degree_Social_Sciences_Archeology.htmlYou can find work as an archaeologist with a BA. Heck, you can find work with just an Associates degree, such as from Hocking College in Ohio. One thing is that you probably will have a tough time finding work if you do not have a BA in anthropology or a related field and no field school. I don't hire anyone without at least a field school under their belt. Keep in mind that some field schools, especially those outside of the country, may not teach you all the skills you will need to work in the private sector in America. But you can go pretty far with just a BA in the private sector - we've had people who specialized in artifacts or GIS who've ended up making a decent wage for a BA-level archaeologist.
You need a master's degree in the private field if you want to be a principal investigator, who runs the projects and generally is responsible for report writing and production. I'm a principal investigator and I actually don't get into the field as much as I used to because my responsibilities (and pay rate) keep me out of the field unless the project requires a PI in the field.
If you want to get into academic archaeology and become a professor, then you do need to get a Master's degree and go for the Ph.D. Having a great GPA is very good, but a lot of schools may be willing to take on a candidate with a 3.5 or so if they also demonstrate the ability to do original, well-thought out research as well.