Well tropical would be the obvious way to go - assuming you have a filter etc in your tank.
There are various ones that are fairly hardy and can be easier than goldfish ime. Eg - Cherry Barbs, Danios, many Tetras incl Cardinal Tetras (not Neons). I'd steer clear of livebearer fish like Guppies, Platies, Mollies etc unless you want to be overrun with them very quickly. See here for suggestions and info on tropical taks
Either that or could you move the tank somewhere else so it doesn't get so hot?
Yep, I would go tropical - but even then, huge temperature variations would cause problems (I've lost fish during hot summers before ).
The obvious things to stop the high temps are:
- is the tank in direct sunlight - can you provide some shade in the summer (blinds/some sort of free-standing screen - don't cover the tank, that'll reduce air circulation).
- turn off any aquarium lighting during the hotter days - lights generate a huge amount of heat.
- main thing is to keep it oxygenated REALLY WELL if temps go up. Is your pump up to scratch? I have a slightly more higher powered pump than I technically need and a valve I can adjust (although you have to be a bit careful, can get a bit choppy in there!)
- in the summer, turn the heater UP. Counter intuitive, but basically the heater only comes on if the temp gets above the setting. Fish die because of rapid temperature change - in a very hot summer, the difference between night and day can be quite large. Gradually turning up the heat can keep day/night temperatures a bit more even and less shocking for the fish (try and not increase temps more than about 1C a day)
- worse case scenario on the very hottest days of a heat wave (hey, you never know, it may happen!) do small water changes (around 10%) every couple of hours with slightly cooler water. Make sure the difference isn't too great again - not more than 1C difference.
Tropical fish are happy around 22C - 28C. The 32C would worry me most - especially if it's for longer than a couple of days. Talk to your local fish shop (LFS) and get advice on the most temperature hardy fish. IME tetras and guppies seem to be the most sensitive to high temperatures in the summer, so I'd avoid getting those.
Oh, I've also heard fishkeepers take the hood off the tank and point a fan down across the water to reduce temperatures. However, I'm reluctant to recommend that, not least because there's a danger of kids knocking the fan into the tank and electric + water don't mix terribly well Oh, plus some fish can jump out of tanks, so I'm wary of keeping the lid off for long periods.
It's not impossible to keep tropical fish in those conditions - especially if you pick the hardier ones. The work involved might be a little unrealistic though, when you really want to be focussed on the kids not the fish on a hot day!