Where to go for dinner before prom in Richmond, VA?

Me, my boyfriend, and maybe 3-4 other people are going out before prom to dinner. I was already looking at Havana 59 or maybe Sine, but I wasn't sure about the atmosphere being right for a formal dinner at either place. The place can't be too far away from the downtown area (Short Pump is out of the question) and should ideally have prices in the $20 and under range for dinner entrees.