Im around, but mopedjay is the express dude - he will find this thread, trust me is the guy. He lives in Haverhill tho
otherwise you would need to find someone around boston somerville that could work on small motors.
I dont want to be a downer, but its not likely the filter, its probably the little express carb full of dirt syndrome, again something jay would be more able to help you out with.
Try and latch onto the boston thread, there is a little group of us that are starting to get a bit...active ( shit i said it )
learning to fix it yourself is the way to go!