Sadly, apartments in Bettendorf don't fit your criteria for nightlife as there really isn't any here (one reason I'd like to move when I can). Regency Apartments look nice but I can't really think of a apartments in Bettendorf that are really close to parks.
I used this link when I was looking for apartments in downtown davenport:
Downtown Living in Davenport, IA
Some of those apartments put you closer to the action than City View or Crescent Lofts. However, I wouldn't hesitate to live in either as the apartments look nice and the walk to the bars wouldn't be too far.
If you don't mind living in Illinois you could look for apartments near downtown Moline and The District of Rock Island. Both are pretty nice and it'd be easy to get to the Iowa side with the I-74 and Centennial bridges.