Firstly, if you want the flat to eat together occasionally, why not suggest it to them? If you have to ask your carer to cook, it shouldn't be a problem - the only diffence between cooking for 1 and 4 is that you have to increase the amount of food cooked.
Secondly, there are plenty of societies and clubs at Uni, and not all of them will involve going to a nightclub type night in the union or wherever. If you make the effort to go to a few of these meetings, you'll stand more of a chance of making friends.
Thirdly, talk to people on your course. See about organising a course night out, perhaps to quieter pubs, so that people can find out if they've got anything in common.
So what if you have to have a carer? So what if you don't think your flatmates are the most interesting people? Don't let it hold you back from enjoying your time at uni, and don't let it stop you from putting the effort in. You never know, you might end up changing your mind about the flat mates.
In short, you never know until you try, so just try and see what happens.