Coding a User Files Upload Quota


I am new to ELGG. and trying to limit users file upload quota to 1GB / User, so thats users cannot upload more than 1GB / ACCOUNt , also I would like to show the progress of it in a DIV like a progress bar about how much space he has left, can anyone please help me out here to how can I do this ? I saw this feature in the TidyPics Gallery Plugin , but I want this for all files. Also I want to make a referral system in ELGG , which I still have not seen in any plugin, when some invites a friend and that friends accept the invite , then the user gets points increase or for example his upload quota increases.