Jade,
This is Jim's wife, Shirley, a dental hygienist, responding. If at all possible save your teeth. I have many patients who tell me they wished they'd done everything possible to save their teeth sooner. Lower dentures typically don't fit well. Without knowing the state of your teeth I can't give you more specific ideas. Do you know if you have pockets, and what their depths would be?
If you still want them all out, I would see an oral surgeon, a dentist who has advanced training in people with more medical concerns, and specializes in extractions. You'd still need to see a regular dentist for dentures. I especially wanted to respond because you are a whole day older than I am! Good luck!
Shirley
To this Jim, who is also petrified of dentists, adds: I recently went in for dental work and was premedicated with the standard antibiotic dosages, but I did not stop coumadin. Although the filling turned into a root canal (worst nightmare!), there still wasn't any bleeding.