She wanted to move in September 15th, so she also paid me for half of September and signed a one year lease.

My question is how do I protect myself to get paid the $550 to $1,000 for finding the property when the person purchases the property?

They have always paid on time, but recently a tenant who just move in just over a month ago wrote to me that she would like to sublease the unit and was looking for my approval.  

Yes, but only if they paid for it.

I am pretty sure there are implications on my end they have a lot of furniture here have paid for moving expenses etc.She has also paid for utilities as well. 

ummm I do this all the time (in reverse) should be a deed transfer and it's super easy.is the house paid for an owned by you?

I found a property and got a buyer but I have the property under contract and I wants to sell the property or contract to the buyer but she has a mortgage to purchase the how do I get paid by that at closing or can someone run me through that process

I have a rental that is fully paid off, but my primary residence carries a mortgage. 

You need to read the prospectus and see who gets paid first.

Cash to seller was borrowed and in process of being paid back.