Try out:
1) Al-Hamrah ( Old Rayyan road )
2) Al Bait Al-Shami ( opposite McDonalds and Butrger king )- Al-Sadd Ramada intersection
3) Al Khaimeh ( opposite Q-tel- Al-Sadd )
They can manage the buffet for you at their place or yours...
The above are suggested places with practicle prices and offer both eastern and western food...
I dont know what type of cussine you perfure..to suggest accordingly.