In terms of prospects, the cost of relievers is pretty high this season. Even Washington's Matt Capps brought a top quality catching prospect from the Minnesota Twins and the Phillies don't seem willing to pay that type of price.
In the days leading up to getting Oswalt, the Phillies were asking about Octavio Dotel, but again, the price was high enough that the Phillies weren't immediately going to make a deal. It's possible that they will check back with Pittsburgh to see if their price on Dotel has changed.
Not many relievers have been moved leading up to the deadline and there are still some guys out there on the market, if their price drops.
As for finding a bat for on the bench, there doesn't appear to be much activity going on, either. It's very possible that the Phillies might wait to see who is available during the waiver trade period in August.
Keep in mind, that things can change quickly and if somebody drops their price - especially on a reliever - the Phillies could find a move to be made to improve the back end of their bullpen.