A Few Questions: Living in Bangkok

I'm moving to Bangkok next week and there are few issues I have with costs for the following 3 weeks, during which time I will be on a tight budget until my next cheque.

1. I need some basic dental treatment, 2 fillings. What might this cost?

2. Food costs per day - not eating out but I'd rather not subsist on a thin noodle soup?

I'll be staying in a hotel.

Thanks