If you want to stay with electric, consider the ParkZone "3D Typhoon" as a next plane. It is complete and comes with a four channel FM radio for around $220 US. If you can fly the Firebird solo and have confidence with it, you should have good sucess with the Typhoon. I would consider it a "proper" airplane as it will do anything a fuel powered plane will do.
If you want to go to glow fuel then seek advice from the local guys as to the plane, radio, engine and equipment you will need. They will be gald to answer your questions and help you get started. We modelers are the same the world over and always want to see new commers to the hobby.