You definitely get a new tub for between 1200 and 1500.
However, do the repair yourself, it's very easy. Use some plywood, resin, and glass cloth, and make your own repair, even if you have to use some thru-bolts to bolt some strengthening blocks to the backs of the holes (just use stainless and it will look good).
And, you could repaint your whole tub easily as well. Best bet for painting a fiberglass tub is to use a "Flex Additive" in your paint, to allow your paint to move when the fiberglass flexes. It'll minimize stress cracks in the paint.
Good Luck, and tell the body shop to pound sand at that price.