Help with financing commercial property

[NA R.]

I have kind of an interesting situation. A few years ago I leased a very large warehouse for my business at a very good price. I didn't need all the space, so I built a smaller unit inside and subleased part of it. I found that to be a very profitable thing to do, so now, that's all my business is. 

I have a long term lease on my building, but I would like to buy it. I would like to use the income from the property to pay the mortgage. I have already leased to three tenants, for a total income of $5200/monthly. I am currently building more units and expect to easily be making at least $10,000/monthly from lease income very soon. The property also has two other paying tenants that are not mine, but would come with the building.

I have only started doing this recently, so I do not have 2 years of tax returns to show. My credit score is about 700, and my total monthly bills (including the warehouse) are about $2000. ($3200 net income)

I'm going to need about $300,000 to purchase the building. Down payment would be a big problem for me. I would be OK with a private lender charging more interest than a bank...but how do I find them? Do you think I would be able to find any kind of loan for this? Even if I lost half my tenants, I would still be able to make the payments.