I've found a few websites, there is plenty to rent in Krakow, which is good, may not be able to get the river view, but should still be able to get a good location, fairly central (hopefully). Also, not in a massive rush, just looking for now, probably won't need to actually start viewing for 6 months or so, so I just wanted to get a rough idea!
vjmehra, don't bother wasting your time searching the websites if you don't understand Polish. I will save you the trouble rent an apartment in - Angel Plaza ul. Zwierzyniecka. Its close to the Wawel and river has a gym and underground parking.