Yeah, good plan going with the 3:1. I definitely think you can find a donor right for you at SG. It just may mean waiting for the right donor to turn up, which is at odds with our torment at waiting longer. And be really proactive with the donor coordinators about what you're looking for.
I hear you, all the wasted time and money torments me sometimes. I have made point not to have all our TTC expense all in one place, b/c I don't think I could handle knowing how much we've spent so far. For me, the time is harder, as I think of all the opportunities I didn't pursue because I thought I was going to be pregnant soon. Like you, I think of things I could have completed by now if I had stopped putting things off because of TTC. [insert emoticon throwing up one's hand and rolling eyes.]
Let us know what you decide. And thanks for you good wishes!