For that budget, I think it is best if you find a venue and get catering yourself. If your house can house the 50 guest, might as well have it at home or another friend's home which can accomodate. Get catering for 40 pax with with a RM25.00 per pax (usually enough) and the rest get a satay caterer and get a few crates of beer (if needed) and drinks submerged in cold ice water. Rent a few tables or maybe tents. With a budget like that, you have to be innovative.

Unless your guest are all big eaters, the food is not important but the event is.