Not a lot of long road climbs in the immediate vicinity unless you head back towards Buhladelah and ride The Lakes Way ... which strikes me as something of a suicide mission: limited shoulders and poor sight lines.
If you're up for a bit of a drive, you could search on bikely for Wauchope to Walcha. My late cousin used to compete in that and used to talk of a 25km climbing section with respect.
If you're prepared to look at MTB, the mountain bike trails at Kiwarrak are awesome. The XC circuit could be ridden on a CX bike if you're adventurous.
It's dirt, but I'm told there's a decent fire road climb heading northwest west then north from near Bungwahl that's part of the Anaconda Adventure Race route. Supposedly great views from the top.
Sorry I can't be more specific. When I'm in Forster I mostly headed straight for Kiwarrak or Old Bar. I'm heading up to Taree/Forster this afternoon for my cousin's funeral tomorrow. If I overhear anything I'll post up more.