I question the fact that her dam "abandoned" her. It sounds more like a bad breeder to me, that left the puppy on the dam that long and expected the dam to keep feeding the pup. The pup should have been weaned at 4-6 weeks and should have already been on solid food by 6 weeks of age. It sounds as if the breeder did not do their homework or fulfill their responsibility to this litter.
For your questions......
First of all, READ, READ, READ!
You are asking questions that are asked here everyday. Here are a couple of posts for you to start with:
http://www.rottweiler.net/forums/pup...uppy-home.html http://www.rottweiler.net/forums/pup...nance-etc.html
After you finish them, do a search (see the blue bar up at the top of the page with the word "search" in it? Click on "search" and enter the topic you are looking for - you will find tons of information on biting and housetraining). There is really no use in us having to give you all the info again when it is readily available through the search engine
With regards to your older dog, is he neutered? I would give them a lot of time with a barrier inbetween them before attempting a face to face again. It sounds as if he has never been around small dogs and with her being a typical puppy who wants to bite and suckle, it is not his fault he does not want her around him.
When you have them separated, give them both equal parts of your time. Don't let him think the puppy is there to take his place. Play with him just as much as the puppy but don't make him be a target for her biting, etc.
When you get them together, have her on a leash so you can control where she goes. That will eliminate her jumping or biting him, you don't want him to bite back! Just the fact that he is running from her indicates that he is not comfortable with her and you will have to re-introduce them at a slower pace so he does not hurt her.
I think that with time and patience he will come around. But in the meantime don't let him be a target of her bites and puppy behavior, that is your job to keep her off of him. Not all big dogs like little dogs. He needs time to adjust to her presence and to get used to her.