bleeding following hysterectomy

I had partial hysterectomy 4/18/09 they removed my uterus and 99% of my cervix, I was sent back to work after 2 weeks, had vaginal bleeding was pulled back from work for 2 more weeks. its been over 3 months and I still have bleeding, started as 3 days every 2 weeks, now the past 2 weeks I have only had 3 days that I have not. Any idea how someone with no uterus or cervix can still have vaginal bleeding??