first off, its an excellent bike. a couple of ways to go here. i would recommend a 34 and 46 for your chainrings if it were me. i would consider a megarange freewheel as well. they go from 14-34 and are available in 6 and 7 speed.

the number of speeds the chainrings are made to handle is not important. they will work with your bike for sure. keep up the good work man! personally i like that bike a lot.