Ceremony portion- did you want anything religious?  If yes, talk to a smaller church and see if minister is available.  If no, do you mind a simple ceremony at city hall? If not, I think you can have some of your friends there to witness the ceremony as well. If yes, go online and find local officiant who is available.  Since your party is small, try doing it on Friday afternoon or Sunday- cheaper and more services available.  Public parks are also ok for gatherings, you may have to get city permit. Look in the yellow pages for party rentals- from chairs to decorated archs.

Reception portion- Chinese or American? Reserve two or three tables- since your party is so small, maybe get a private room.  If you want flowers, I would go to Cosco or any smaller florist since you only need two or three bouquets for the tables, and something special for you and groom. 

Plan it like a party- try not to mention wedding to the vendors since yours is smaller than most and not necessary for vendors to add cost just because it is associated with wedding.

Good luck.