There are a few possible causes that can produce a no heat problem. One and the most likley cause is that you blend door is not operating properly. The blendore is exactly what it sounds like its a little door in your dash that switches back and forth and changes the amount of hot or cold air that passes through the vents. Another less likley cause is that your heater core is stopped up. The heater core is a box in your dash that hot coolant from the engine passes through then air is passed through the heater core and voila hot air. It may be possible that either the heater core itself is blocked up in which case you have to replace the core or a valve that controls the coolant flow to the core is not opertating as it should.
In response to the heated seats it could be a number of things. Such as the electric heating element in the seat, the operating switch is faulty, a problem with the wiring, or a bad power source. Any of these is a likley cause and an automotive technician or a person you know that has an undestanding of electrical circuts and a means of testing them could probably diagnose these faults further. What you could do is verify that the fuse is good. Check the fuse panel and look at the diagram either in a service manual or on the back of the fuse panel cover and see if you can find any one labed seat heater, heated seats, power seats, or any thing that may fall in that catagory. Pull the fuse out and look to see if it is blown. You can tell by tha little " s" shaped wire on the inside is burned or not connected, if its blown then replace that fuse with one of the same rating, you can find the ratting at the top of the fuse ie 10 20 15 30 35. Also I would chaeck and see if both seats dont heat up if they dont then its probably a common problem like the power suply or wiring. Hope this helps.