I'm sorry that you haven't received more answers. It's a complicated situation, and to be perfectly honest, I think that this is an expense you'll probably just have to eat. I don't know of any service or forum that allows the selling of "private market" sperm.:) (MDC does not.)
If you do want to sell the vials, I think your best bet would be to write out an email explaining your situation, and just send it out to everyone you know, asking them to forward on to their networks. I have friends who passed on an extra vial of sperm this way, though they weren't looking for any $$, they just wanted someone to take over the storage fees. You know, the power of queer networks and all... You might also ask your KD if he knows anyone who might be interested. Most gay guys I know have a long list of lesbians seeking their sperm...
I would also encourage you, if you can't find a buyer, to consider donating them to someone who might not be able to afford sperm otherwise. I understand that you spent a lot of money on this and want to recoup, but if you can't- there are many people who will make excellent parents, and desperately want to be parents, who are priced out of the queer fertility scene. I would gently discourage you from only wanting to share your sperm with someone who can afford to pay for it. Some of the best parents I know would never be able to afford sperm from a bank.
I actually got pregnant initially with leftover sperm that someone gave me. I was a grad student back then and living on a very limited income, and it felt like an amazing gift. Now my DP and I are both successful PhDs. We make decent money and could buy our own sperm if/when we TTC again. But back then, it was a huge, daunting expense for me, and I'm glad that some stranger's generosity made it possible for me to accrue a little less debt on the path parenthood. I guess what I'm saying here is that the lack of ability to pay $2,000 upfront for sperm - an amount of sperm you might not even need - does not preclude excellent parenting. I ended up miscarrying my first pregnancy and taking out a student loan to buy more sperm. I have a daughter now, and actually own extra vials of sperm from her donor. I often think about what I would do with those extra vials if we end not needing them, and for me, the obvious answer is to give them to someone who can't afford to buy their own. Even though I still have some debt from them, I guess I just see this as my opportunity to pay it forward. And as a recognition of my current place of relative economic privilege, and a desire to contribute to a world of queer parenting that doesn't create barriers to access for those with less money. So, that's my $0.02 on that.
I also might add that though you're talking about a price that's much lower than that of some sperm banks, you get other services with a sperm bank as well- the ability to switch donors if things aren't working out. The knowledge that the bank will notify you if there's ever a reported medical issue with your donor or donor siblings. Access to a donor sibling registry. The ability to transfer your sperm to someone else if you ever decide to, without any ethical issue. Paperwork to help in filing a second parent adoption. So, these are all reasons why what was a very good deal for YOU (using a KD who you had a relationship with), might not be a great deal for someone else.
Best of luck in your decisions, and congratulations on your pregnancy.