- Interpreting the Evidence: Pompeii and Herculaneum (Brian Brennan & Estelle Lazer)
- Cities of Vesuvius (Pamela Bradley)
- Secrets of Vesuvius (Kate Cameron & Jennifer Lawless - not recommended)
- Antiquity 3 (Toni Hurley)
- Excel Book - Ancient History
There are endless sources on the use of the fora in Ancient Pompeii. These particular sources look at graffitti, the works of Pliny the Elder, etc.
Also looking at the Roman Capital - Rome - it is reasonable to include that the fora would have much the same function of the city of Rome. Find some sources on them; Strabo, Livy, Pliny the Elder, etc.
You will ultimately need to make it Pompeii-specific however, dont take too much from Roman Fora.
I actually have an exact article on my site here.
http://arcanehistory.com/?p=38
Cant do the assignment for you but there are at least some sources you can use. I wouldnt exactly say they are hard to find though.