Laurence and Hisoka, I don't think it's a requirement that you
have to cook something to go to the Potluck. I believe the whole
idea of the potluck is to bring something for everyone to share and
the main objective is to socialise . If you can't cook, just buy
something from the shop or supermarket. Depending on how many
people are going, find out who is bringing main dishes, snacks
(appertisers), desserts, drinks etc.
If no one is bringing snack food and drinks, perhaps you can
consider bringing along a few packets of chips like corn chips with
salsa dips, a case of soft drinks (depending what people prefer to
drink), biscuits & cheeses, fruits platter etc.... If there's
no enough main dish, bring some Satay (takeaway) from the stalls or
similar....
Hope the ideas help and don't get too stressed out about what to
bring and just enjoy the gathering. I wish I can be there to try
out the nice food people are bringing especially Mr Bear's popular
braised duck. 
