I was going to suggest that you set up a dating profile in the Boston area because that city is crawling with poly & bi folks...that's what I did even though I live an hour and a half outside of Boston (in southern RI)...but since you can't drive, um, no, that won't work.
Seriously, how do you even live in NH if you can't drive? That's nuts. Do you have any plans to learn to drive?
I don't think you come across as desperate--I think you're right in that you come across as too independent & free-spirited. (I have much the same problem). I think it's awesome that you are clear about knowing who you are (bi and poly) and what you looking for (poly and bi-friendly). I wouldn't compromise on those things. I too would rather be single forever than monogamous. And you will eventually come across people who appreciate you for who you are.
However. You're gonna have to a) learn to drive and get a car, or b) move to an area with public transportation. There are really only those two options. How could ANYONE hope to find someone who lives within walking distance of their house???????
Or, make fliers out of your OK Cupid profile and shove them in all the mailboxes you can walk to near your house.