How to borrow more money for investment properties

[Hoang P.]

Hi everyone, I don't have much experiences in borrowing money and would like to ask for advices. Here is my sum up situation:
I bought my 1st rental property in Oct 2008. Currently I own 5 rental properties + my Home. I don't have any mortgages except for the $90K equity line of credit I took out on my Home to buy the last 2 rental properties. So right now, all I owe is the $90K on the equity line at the interest rate of 2.74% with a payment of $190/month. All 5 of my rental properties are renting to Section 8 tenants for the total of $5050 per month (all 5 properties are on 1 year lease with Section 8). I currently don't have a job with a credit score of 725. My wife is working with a salary of 45K/year. Her credit score is 840.
My question is: how do we go about borrow more money to purchase more investment properties? What are my best options? Any suggestions is greatly appreciated. I'm in Louisville, Kentucky BTW.