There is also a place called biotrack.
If you can get redtop blood tubes from your local vet, you can draw blood and send it into them and it is 7.50 a piece to run it for pregnancy. You can pay at the time that you send the blood, or you can be billed at the end of the month. They will email you the test results. I have had alot of contact with them, as I am doing 3 of mine and 1 of a friends.
They only have to be I think 25 days gestation for the test. There is a link to their website on mine if you want to check it out!
Just a thought~