I can not answer your question, but do suggest you maybe speak privately with an IVF specialist. I believe that a number of women have carried full term ivf babies after an abortion but it may be too soon at this point depending how far along you were and the type of procedure done.
Your sister does not know that you had the abortion, I take it, and you don't want to tell her? (ps - I hope you have broken off with Mr. Inappropriate. It's not a good sign when you cannot introduce your suitor to your family.)
Anyway, if a woman loses a pregnancy early in the pregnancy from a miscarriage, doctors will tell her to wait at least one full cycle (most will say two) to be sure all is normal in her uterus before she tries to get pregnant again. If she were to need a D&C, some doctors will tell her to wait longer, but others will encourage her to go ahead, because there is some not-quite-proven documentation that a slight irritation to the uterus (such as a biopsy) can increase a woman's fertility. (If you had had a C-section, they would tell you to wait 6 months, but that is because the uterus itself gets cut open.)
You should talk this over with the IVF doctor for sure, but if you are going to try to keep the abortion a secret from your sister, you will need to arrange an appointment where your sister is not present. This is because the doc will almost certainly ask if you have ever been pregnant before. If the abortion was your first pregnancy and if you are keeping it a secret, his asking you when your sister is in the room would cause you to have to lie or reveal. But the doctor does need to know, it actually makes you a better candidate to carry a baby because you are considered to have a "proven" uterus.
In short, the abortion does not rule you out and in one way makes you a better candidate because it is clear you are able to get pregnant. But the doctor needs to know, so make your plans to meet the doctor (with or without your sister there) according to what you are trying to keep a secret from her.
I'm not offended by what you did everyone has a choice, but I'm in love with what you are trying to do for your sister. I would talk to the ivf doctor and see what they say because I have seen lots of people that get a abortion and get pregnant with no issue. I hope that everything is going ok for you and keep us posted on what happens I would love to find out