Apartment-style HVAC

[stacyh3]

I have a getaway place that has a through-wall heat/AC unit. It's a multi-tenant building with central controls of heat/AC, but where individuals have some degree of fan control and temperature. The problem is that for fan settings you have OFF/LOW/MED/HIGH as your only choices. The fan never shuts off when the temperature reaches the desired level!

Does anyone know of a commercial product that would add fan control in? How about a DIY solution?

Thanks!
Stacy