Sounds like you had fun
The great thing about a dingy is it teaches you to react quickly, as soon as the boat feels like she is about to go over, you gotta get the mainsheet out. At first, you'll be dumping it when you didn't really need to, but as you get more used to it you'll get a better feel for it. You also won't be able to get her upright again after a capsize unless the sheet it completely free to run, perhaps a little float at the top of the mast might help if you still have difficulty, I know a lot of the hobie type beachcats use them.
As for getting back onboard, you should be able to scramble in as she comes upright. I don't think a motor is going to work if you are likely to be spending time under water, just going to need to learn to row better, or sail in a little more wind to get back to the dock