If your parents/in-laws want more tables and exceeding your budget, try to ask them to pay it first and you repay them when u get the red packet. If you dinner is not very expensive, the red packets should be enough to cover it.
My friends had their wedding at Burnaby village. They have a nice chapel and the garden is good for photos. I think it's less than $500 including the commissioner. But the chapel is not that big, only for 70 ppl