Mike is certainly on the right track by recommending using the Health Department or any other public entity as a resource. You might want to consider having an engineer give you an opinion of what they feel is going on and what it would require to correct it.
In my experience in dealing with banks I have found they are more willing to do a price reduction when asked for repairs. You should gather estimates and talk with as many resources as possible to determine the worst case scenario of fixing the issue. The good thing for you is that this will likely come up with any other buyer as well.
Do not let the "As Is" clause scare you. It does not mean they will not do repairs or lower the price.
Definitely get a well/septic inspection. It should only cost a few hundred dollars and will be worth every penny. The basement dampness could be thousands of dollars to repair. You are best served getting estimates for the work and presenting those with your remedy request.