how to increase user quota

[expunge]

Firstly let me say that I trid about 6 other galleries but this is by far the best. Still don't understand how to configure groups but at the moment that does'nt matter.
The problem I have is how do you increase the user quota from 1024 to something bigger. Is it the size of your hard drive or the amount of space on your server. I have 500mb on my server and 30 users, not all will be putting many photo's up.
What size do you recomend alloting each user and how do you do it.
Thankfully expunge

[Nibbler]

It's on the groups page.

[expunge]

Thank you for your help. Problen solved