Is there any types of exercises out there that will help me lose the fat that has settled in my stomach after surgery (hystorectomy) without losing my breast size? I can't afford to lose there! Any advise?

Well usually you'll lose some size, but the body will take away from that area last usually, like when you get around 12% bodyfat it'll really take away from your "chest". But theres not much you can do about a little loss, well except for implants but I dont think you were thinking of that lol.

I have been working out for about a month and a half now and have been loosing inches and pounds, but my breasts really havent' gone down in size too much, if at all. I wouldn't worry too much about it =)

lol thats something i'm scared of. I hope I don't get too small after I get to my target weight.

You wont have to worry about any real losses until your at a very low body fat. But a little loss is inevitable, it is fat.

as long as I'm not a A cup then I'm fine.

Start doing chest exercises. Push ups'll do ya.
Although the fatty part of your breast is likely to decrease as you lose fat, the increased pectoral muscle can make up the difference.

After I started working my chest I went down to a 34 from a 36, but went UP a cup size (and I really, really didn't need it).

Good luck.

hmm I notice that a lot of really fit women who have a lot of pectoral muscle don't really look that feminine.. well still feminine, but they have that "pre-body builder" look, where they have a really big upper body, and small boobs, but they aren't quite as muscular as a body builder. Do you know what I mean?

Well I think it all depends on your body type and where you hold your weight,...for a large person I hold my weight porportionally all over, and have lost it the same way...so yes bust went down but so did the rest of me so they still look in porportionate. Actually I think the chest area does look better due to the chest excersizes.
However if you are top heavy, or bottom heavy or slightly overweight or have more to loose I think all plays a part.

Bottom line you cant really do anything about it....other than excersize the chest area....or buy a good bra!

hahaha bras are the best things thats ever happened to women in life. Hmm.. or maybe it shares the spot with tampons.

Usually when fit women look like body builders they are getting ready either for a show or some kind of photo shoot and they mostly start to look more feminine after they lighten up on the training. So you don't have to woryy about getting like them with just some pectoral work because you will probably not be doing as much specific training as they are going to do.