Thanks for the replies, guys.
I'm working 40 hours a week at the moment before I start at the conservatorium, and I can only fit in maybe two or three hours a day practice.
I play in three bands (only one of which I play piano) so I guess that also counts as practice. I also do play in bars and stuff with the piano band. I don't know whether playing bass in a hardcore band counts really, or does it?

I guess I'm learning a different type of music there, so I suppose it's all good.
Anyway, my job is as an architect. So, basically, I draw toilets and basins on the computer all day long. I think it's probably an OK job to have in terms of not being too worn out to practice piano, but the stupid chair at work does give me a sore back. In a way, I'm scared to let this job go and work in a piano-related field because I've had this job for three years and it's a security blanket, but I'm going to leave it eventually, so I might as well do that soon, I guess.
Don't let the age thing bother you, ChopinFreak! I'm 25 and I got into my first-choice conservatorium (admittedly this was after I started when I was 12 but I don't think your late start should hinder you at all really). I think some places might only take people under 21, but that's OK. You can just go to a different one.
I think it's a real bother having to practice and work full-time, and it's a bit easier for me because I know I'll be working part time soon so I can put up with it. But I've found that if you can get an hour or two in of the boring bits of practice you have to do before work, you'll want to do some fun piano stuff after work for another hour at least.
As for sight reading - just keep at it and don't ever get annoyed at yourself! Reading music becomes easier and easier all the time, and you'll be totally fluent in it soon.