BBJ Linen
Alyssa, I have worked with the above company many times and they have great quality and selection. I will warn you, they are the most expensive I've ever come across. Plan $25 per linen, plus shipping.
WeddingLinens.com
This is another comapny with a large selection, though I have never personally worked with them.
You might want to look on e-bay and see if you can buy any in the right color wholesale. I can't remember the name of the seller I used before!
I would suggest contacting the local rental company/hotel and see if you can sell them the linens when you are finished, especially if you will be renting other items. If you will have to bring them back with you, see if there is a company at home you can sell them to.
For the difference in price, I would suggest a 108" round instead of the 120". A lot of times tables can be uneven or the legs are a weird height. More often than not, I've seen linens that were too big that puddle on the floor. The 108s still give a floor length look and you never have to worry about them getting stuck on a chair leg.