Sorry to say but you can't really convert them, in fact it's even difficult for us developers to do so with our own games because they speak completely different languages (iPhone is programmed in Objective-C and Android is programmed in Java), so the games have to either be re-written in the other language, or originally created on some kind of multiplatform SDK like Unity.
There's one simple reason that iOS has more and better games though, it's the lack of support from the gamers on Android. Because Android is open the users have much more of a tendency to want the games for free, whether that means pirating or just ignoring most of the paid games. Generally developers don't put much enthusiasm into getting their stuff on Android because Android games don't seem to make money, and this is the only reason Android versions of games either come late or not at all.
The best way you can help Android to catch up with iOS is to support the developers by buying the games. Generally they're fully interactive video games which are cheaper than the cup of coffee you're probably drinking while reading this (though some developers use the tactic of charging more on Android to make up for the lower number of sales). If everybody forked out a couple of dollars for games more often, Android wouldn't be so left behind for software.