Is the thermostat still clicking on & off when you turn the temperature control ? If so it's most likeley to be the element. I've just replaced mine, for the main oven on a double appliance. I had the same symptoms, fan but no heat.
If you have any doubts regarding working with electricity, get an electrician or competent person to do this for you.
Inside the oven there will be a plate over the fan secured with screws. Turn off the power at the cooker switch before doing anything. Take off the plate & you should see the element, it will be secured with more screws. Remove the screws & carefully withdraw the element. There will be 3 wires connected to the element, make sure they don't fall back onto the the hole that they poke through or the oven will have to come out & the back panel removed to retrieve them !
You should be able to see some slight discolouring on the element.
New elements are relatively cheap to buy, around £25 to £30 from high street spares shops, or if you have internet access, you should be able to get one for less than £10 from ebay etc...
Hope this helps !
Steve ward., April 2008