Toyota Yaris and (I believe) all Scions have EPS (electric power steering) as well.
I would agree that the mr2 pump is about the easiest way to go. I had to have one pressure line made for a $60. I reused the oem fitting that screws into the rack.The nice thing about the MR2 pump is you use stock steering components which retain the proper steering geometry. It is never as simple as just swapping in an electric rack, etc... Steering systems are very touchy and must be designed for the car. This idea could cost some safety points. Of course, if you have the know how to modify the system it would be a worth while project. IMHO, save your labor time (my hours are worth more than that, I'll just get an mr2 pump) and know it's setup right