Coliform Bacteria is not unusual in a well and its treatment is easy enough to resolve. One method is to simply add Chlorine Tabs, though this will be an on going treatment. Another is the installation of a UV light.
Any plumber should be able to set you up with a fairly non complicated water filtration system and UV light, but if you just want it to pass for a sale, then the chlorine tabs will do it.
The Water Source in Wappingers Falls is a good company.
All you really need to do is shock the system. You do this by pouring bleach combined with water right into the well. You let it sit for a couple of days and then you run the water in the sink until the smell of the bleach disappears. The Board of Health will provide you with the %age of both bleach and water to use. They will also provide you with testing jars. After you have gotten a clean sample, you bring it to the board of health for retesting. There is a fee for this. If you want a more thorough testing done, call Smith Labs in Hyde Park. Again, you go and pick up the materials, they explain to you how to perform the test and then you bring it back to them.
If, however, you are in the process of sellling your home,, be aware that the town of East Fishkill has a mandatory well test prior to their releasing the municipals. If this is the case, call the town. They will give you a list a certified well testers who will come out and perform this job. This type of well test runs in the market of $600, but you can't sell your home without having it done. Good luck. Let me know if there is anything else I can do.