This is a good question, and one that many agents don't stop to ask, so I applaud your inquiry. It is actually a little bit more complicated for your situation than everyone is letting on.
Your broker will be able to confirm specifics of what you can do as you practice real estate at the privilege of his/her brokerage, and many options that MAY be legal to do, may come with risks that your Broker is not willing to take on. However, I can give you some options and things to think about with each option.
First let me say that LDAs (Limited Dual Agency) are awesome when used appropriately. It is great to "double dip" on a transaction.
However, I think you will find that you will not be able to represent the Buyer and yourself in the transaction as you are not able to provide the same level of service to each party since you have an ownership interest on the seller side. Let me explain....
In a regular LDA (Limited Dual Agency), either 1 agent represents both parties, or 2 different agents from the same brokerage represent 1 of the two parties (1 for the Buyer, 1 for the Seller). Remember, it's all about the Broker. With LDAs, your representation is limited because there are certain things you have to protect from one to the other.....for instance......Let's say the Buyer tells you that they would be willing to pay closing costs if the Seller counters with that. IF you go and tell the Seller that they can counter on closing costs because you know the Buyer will pay them, you have just violated your duty to the Buyer. In a NORMAL representation, if you would have heard something like that, you would run to the Seller and tell them because you only represent the Seller and their interests. However, in an LDA, you have a responsibility to both and cannot disclose certain things about either party.
So, do you see now why YOU being the Seller representing themselves AND representing the Buyer wouldn't work? Because obviously anything the Buyer would tell you would provide you an advantage.
You still have options....again please counsel with your Broker to see what he/she allows.
The safest option is to allow the Buyer to obtain their own agent, and not make any suggestions. That way, any advice the agent gives them is not related to you in any way, and you limit your liability.
Another option would be to suggest another agent within your office. You would then be in an LDA, but it would be ok because the Buyer had a representative that wasn't the Seller himself.
You could suggest another agent from a different brokerage as well. You wouldn't be in an LDA at that point, and you could ask for a referral fee.
You could be the sole agent in the transaction and treat it like a FSBO in reverse (where the Buyer doesn't have representation) and you represent yourself (a written disclosure will be required where the Buyer acknowledges that you represent yourself and not them).
Lastly, you will have to ask your broker if you can even represent yourself. Many agents don't realize this, but when you represent yourself, you do not have the protection of E&O insurance as any error or omission is considered fraud on your part. Many brokers will be your agent on paper as a professional courtesy to avoid the E&O issue. Just another thing to consider.
I hope that helps clarify things. Best practice is to consult with your Broker for his/her policy on Dual Agency. Best of Luck to you!!