Best option is to move everything to the mini using an external hard drive. Copy all the contents of the itunes music folder over to that, then nwards to the mini.
Also, you might could use iPodDisk. It will let you pull all the stuff off you iPod if you don't have, or don't want to get an external. (I'm not sure how well that will work with your iPod currently being formatted for PC, I don't seeing it being a prob, but you never know.) I just used iPodDisk myself, works great.
Congrats on the mini...you'll love a mac if you haven't used one.