Nice one.
A barlow will give you the extra magnification that you desire.
Andrews Communication have a 2.5x Apo Barlow that I think well of. It's optics are lovely and it's very reasonably priced too at $49.
http://andrewscom.com.au/site-section-10.htm
It's listed in the Guan Sheng Accessories page, scroll down near the bottom of the page.