I'm guessing that you got most of the actual pumpkin out when you filtered into your primary, and I'm not sure putting it through another filter will make that much of a difference. I mean, it will help, but it will probably take a long time for probably not that much benefit.
I would definitely rack into a secondary using some gelatin. You can get the gelatin at your LHBS -- honestly, I don't know if it is the same kind of stuff you would buy in the grocery store.
Two important notes when using it:
1) The colder you can get your beer, the better the gelatin will work. I don't know how practical it is for you to get the beer cold at this point, but gelatin works better the lower the temperatue.
2) When you mix the gelatin, give it some time to "bloom." In other words, mix it, wait about 10-15 minutes, and then pour it in. Don't just mix it and dump it.
I'm not sure how much even the gelatin will help, but I think it is easier and has a greater chance of success than filtering.
Most pumpkin ale recipes I see seem to include using Irish moss during the boil as opposed to gelatin at the end -- maybe this is why?