Very much so.
RW had 100 day schedules for halfMs starting in the July issue so that gives you plenty of time (should be able to find them on this site somewhere).
Congratulations on the 10km time, I personally recommend the schedules although remain relaxed about sticking to them regularly. The key sessions are the weekly long runs, and if you can muster the energy some speedwork (start with a few reps) and in time you'll not only see an improvement in your stamina, but also in your overall times.
Word of warning, winter training can be a bugger (cold weather) but it makes you appreciate the summers, also keep an eye on the events forum, loads of spring events , and there will be loads of forumites running.
Good Luck!