Hi Candace,
I have one bio baby (he's 4 1/2 now) that I nursed 3 yrs. If you're wanting to keep you milk flowing for 3 months, I think you'll have to do a lot of pumping and nursing (nipple stimulation). You might have to get creative that way. I also found that later in my nursing experience, I had gotten careless about drinking fluids. I would intentionally drink gatorade for couple of days and get in some extra nursing and that would increase my supply pretty quidkly.
Overall, you'll need to pump / nurse / stimulate on a nursing frequency schedule if you want to keep you milk flowing. It's a supply and demand thing.
Good luck!
Laura