If you're undergoing fertility treatments like that, then you should already be having regular doctor visits. The doctor will be able to tell you far sooner than anything you might do on your own. Just be patient, and good luck.
I would suggest getting a hold of your doctor and asking him how long it may take. Only reason I say this is that everyone is different. I believe that you can find out naturally in a few weeks, though I am not a medical professional.
You certainly are not going to be able to tell right now. If you were implanted during your ovulation period then you have to wait about four days before your missed period to test. Believe it or not most pregnant women do not find out until they are about a month pregnant.
I shhould take at least 2-3 weeks. You have to let the gestation happen. Its good to be patient during this time and not to stress yourself out as this will effect you. Since tour working with specilists during this procedure they tell you as soon as your pregnant.
Just like with any pregnancy you must be three to five days prior to your missed period, but with you having taken HCG hormones you should wait 14 days after the transfer to test to make sure that the medication from the shots are out of your system and that you will not get a false positive.