How to print in center of platform?

My printer always starts printing at "home", which has never been a problem until now. I'm wanting to print a handle, but part of the handle is right over the dump area. How do I tell the printer to first move the y-axis by a 100 or so and then start printing?

I use skeinforge to generate the gcode and then upload the gcode in repsnapper for printing.

Multiply module in skeinforge, tell it to print a 1*1 grid of objects centered on 100,100.

Thanks Andrew. That worked