You should not "need" an exporter/importer. I still have a few firearms in Canada (held by a friend) that I will sooner or later get around to importing. I talked directly with the ATF on the phone late last summer. Basically, once you have selected your FFL, and fill out the ATF form 6A (which is quite intensive, but still, it can be done by yourself), your FFL will send it to the ATF and then they will instruct your FFL what to do next. The guns will be MAILED (yes, mailed) to the FFL once ATF has done the approval process and grants the permit. Initially the ATF guide says an importer needs to purchase an importer permit ($250 a year), but this paragraph below seems to agree with the woman I talked to at ATF about half-a-dozen sporting firearms (FORGET about importing anything that was used in ANY military anywhere in the world):
This is from http://www.atf.gov/files/firearms/guides/importation-verification/download/firearms-imporation-verification-guidebook--complete.pdf
A holder of a Type 01, Type 02, or Type 07 FFL respectively. A licensed dealer, pawnbroker or
firearms manufacturer may occasionally obtain an approved ATF F 6 (Part I) import permit to
import firearms and ammunition for his or her own use, for repair, or as the import agent for a
specific customer. A licensed dealer, pawnbroker or firearms manufacturer may not import
firearms or ammunition for resale or other commercial purposes. 18 U.S.C. § 922(a)(1)(A).
Initially, I too contacted a couple of "specialty" exporters/importers and was given the fee of $100 per long gun and $150 per handgun. Thanks but no thanks.
Do a bit of digging. It has been almost a year since I talked with ATF but it's worth your while to call them and ask about the procedure (I've got to call them again since I was "too busy" last year to find a FFL who would be willing to undertake the importation).
Oh and of course if there are restricted weapons involved, they will have to be "de-registered" in Canada prior to importation to the US. Contact your friendly neighborhood door-kicking-in Horse Fuzz to inquire about that.