I'm so sorry you're going through all this, and mama, let me bow down to you right now as the GODDESS of BFing for doing everything that you've done with NO support and NO help.
Please, please get yourself ASAP to
http://groups.yahoo.com/group/apmultiples and join and post this post or something like it. There are many, many women on this list who have had twins, even triplets in the NICU and have eventually gotten them 100% on the breast. I have seen it happen over and over again on this list (yes, even triplets!). But it is a long road and you need really good advice and support and this list can help you get it. Please don't be put off by the "AP" in the title--we are all MOMs who have widely varying ideas of what AP is and BFing (or doing one's best to) is a major focus of the list regardless of other parenting beliefs. One person who is on this list who can be a major help to you, I think, is Karen Kerkhoff Gromada, author of Mothering Multiples, who can give you direct help and possibly connect you with an LC locally who is experienced with multiples/NICU/preemie issues and can provide some real help and navigate the politics in the NICU.
I'd also recommend getting a copy of Karen's book. Most LLL groups have a copy in their libraries (LLL publishes it) or the hospital library might have it. It has detailed chapters on managing NICU time to get the best start on BFing. Here is Karen's website too (she just put it up so there may be missing links):
http://www.karengromada.com . Even if you don't join the list, please email her and mention my name. She *will* provide really useful help, I promise!
I was incredibly lucky to have an easy start with nearly-term babies but from hanging around that list I have learned a lot. First, it's normal to bottle feed preemies and it doesn't mean that all is lost for bfing. It will just take work. A qualified LC can help by giving some tips like using BF cues to bottle feed (tickling the baby's lips and waiting for her to open her mouth wide before putting the bottle in, using slow/no flow nipples like medela's haberman feeder, and others Karen can tell you). You can transition the babies to the breast over time, and it often doesn't happen until their due date or after, even with the most dedicated work. It's AWESOME that you're pumping enough for them--keep it up! That is really great and not everyone is able to do that right away! Also, your instincts are right about not double-nursing yet. That will come in time, but until they're bfing effectively (or at least one is) that probably won't be realistic.
Hang in there mama. You can do this. It's a hard road, but it's one many have travelled before. Your babies are sooooo lucky to have you!
I hope to see you soon over on the APMultiples list.
((((HUGS))))) there supermama!
Cate