I need help with a mac!!!!

I have a iMac G3 333mhz (dont laugh, I am giving it to my sister for her birthday) and I have a new hard drive for the machine. Problem is when I start up the machine I get the apple folder guy and a question mark. I would love to just install a clean copy of 10.2 but I don't have the ribbon cable to connect to the built in cd drive. I do happen to have an external usb cd drive but the thing doesn't want to boot from cd. Is there any command or anything I can do to install 10.2 on the machine? or if someone knows if its possible to grab an image online and write to it on a windows machine? Thanks