Swapping Hard drive with only a usb external

I am new to Macs, I recently purchased a Macbook MC240LL. It came with leopard, I believe?, 10.5.8 and no recovery disk.

The problem is it only has a 160 GB hard drive and its pretty close to being full. I have a 320 GB hard drive I would like to use, but I am not quite sure how I go about swapping from one to the other. I do have a USB 500 GB external hard drive to use for the transition.

The question is:

1. After making some sort of "back up" with some thing like Carbon Copy(?) Can I install the bigger hard drive(the 320 GB), boot the mac, and install the "image" from a USB external hard drive? OR can this only be done with a Firewire external?

2. Also the 320 GB hard drive is currently imaged for a PC computer with windows. Will this be a problem? Before I have used windows recovery disk and had the options to erase hard drive before installing a new image. However I am in the dark on this situation.

Thanks in advance for your help and support!! Also take it easy on me I am not up to par with the lingo used for OS X yet. For example I am unsure what disk utility is?

Clone your current internal hard drive to the external drive. Carbon Copy Cloner and SuperDuper are the two top recommended utilities that we recommend. Once done… boot off the external hard drive to ensure it works to your expectation. Then shut it down; remove the battery; then replace the internal drive. Pop the battery back in, then boot up off the external drive once again and clone it back over.

And as a suggestion puy Snow Leopard $29.00 Apple Online. Mush faster than Leopard and you will have the disc.

http://store.apple.com/us/product/MC573Z/A