Well at least it was a nice day Adam, it would have been lovely and warm in your "shed"? Is that a small red worm poking his head out of that rust hole in your rim, or have I been over-imbibing?
It's entirely up to you whether you get those holes filled, I've brazed up some small holes in rims before having them re-chromed before, but it's up to you mate, you're gonna be riding it.
You can buy new rims from any number of sources, it's probably easier to buy new ones now than used ones? Cheers, Terry.