Wheels and tires...

I have 20" rims that need some attention. I have been using Toyo Proxies S/T since the life of the rims. Last season while taking off the rims for the stocks to go on for the winter, I realized that the tires were completely bald. I purchased new tires through a friend for an incredible deal. I am using the same tires, since I liked them so much. The problem comes into play when trying to find a place that can actually remove the old tires and put the new ones on the rims. I live in Northern NJ and was wondering if anyone knows of a place that would be able to handle such a task. I was thinking Firestone but I am not sure. There is always the possibility of bringing them back to the original store I purchased the rims at but I am sure that this is going to be a rip off. Any suggestions?
P.S. I rather not cart around the rims in my truck to have places tell me they can't do it. Time is limited as this needs to be done by tomorrow afternoon.