There are several issues here -- and given that the amount of money involved is $6,000 (which is a fraction of what normally what would d have to be involved to make it financially worthwhile to bring a lawsuit or have any successful lawyer take you on as a client) perhaps the most important is maintaining family harmony -- or whatever is left of that. Considering having your sister arrested on felony charges is NOT one way to achieve harmony.
You said your sister is the executor. While a Will may name an executor, the appropriate probate court has to officially confirm the appointment and issue an order confirming that she is the executor. If there was no Will an heir would have had to go to the probate court and seek to be appointed administrator of the estate. In either event your sister presumably have filed the Will for probate (of if there was no Will, become appointed) in the court in the county where your parents resided and/or owned the real property.
You may want to go to the court house and look at the probate file and get an understanding as to where things in terms of your parents' estate. The probate file will also likely show the name of any lawyer your sister retained. As she told you that "the lawyer is working on it" -- and these things often take time as lawyers will want to make sure there are no claims outstanding or filed by any creditor of your parents before they say it's okay for assets to be distributed -- you could then contact the lawyer and ask where things stand in terms of your parents estate and when you can expect to receive a deed for the property you say you bought.