Just stick to the set you have for now and get some eyepiece time BEFORE starting out on the accessory trail. Before more eyepieces I would say you need a red torch, planisphere (the large Chandler one is great), observing chair (otherwise you will get dobber's back
), cheshire eyepiece (for collimating), a Telrad, a good basic atlas like the Bright Star Atlas 2000.0, a variable polarising moon filter and a basic moon book like Discover The Moon by Jean Lacroux, Christian Legrand, Christopher Sutcliffe. With this little lot you will be well and truely off and running.
Another thing to do is to get along to your local astro society and see what is used and why in the accessory market.