There are loads of different electrolytic caps you can try in the Quickie. I believe the smallest value you want is something like 47uF, and the highest value is whatever will fit under the chassis. DC voltage rating should be 6V or higher.
On the 2.2uF cap, there's also some allowable variation there, but I would recommend staying over 1.5uF. Any film cap that you find is going to have an acceptable voltage rating.
-PB