I really want another Hulk film...although it seems they have no immediate plans for scheduling one and are just going to use Ruffalo in "Avengers" and such which I think is a waste of his contract, but perhaps they do have something in mind for phase three and could resign him. I believe he has a three picture deal?
As for Betty Ross...I don't believe Liv was contracted for a sequel to "The Incredible Hulk". In fact in the audio commentary Tim Roth revealed he had a contract for the second, so if there were sequel contacts they must have since expired.
I like the suggestion above that Bruce has distanced himself. I'm sure he and Betty had reached some kind of understanding and they're in contact but I got the impression from "Avengers" that he's been keeping a low profile like the start of "The Incredible Hulk".