The facts you presented are 1) you bought your current home 4 years ago with a mortgage 2) you need to avoid paying mortgage payments on two houses 3) you don't have much business experience.
If you are looking for wise advice based on real-world, first-hand experience with rental property investment the short answer is:
1) DON'T purchase another home before you sell your current home
2) DON'T even consider becoming a landlord until you can afford to carry both mortgage payments.
The risk involved with the situation you describe is very great that you could lose both your current home and the second one you want to buy! All it would take is a tenant that fails to pay their rent for a couple of months, requiring you to hire an attorney (can you say $$$?)to get them evicted. In the 3-4 months of no income and double expenses, your financial well-being might well crash and burn. Believe me, this happens every day of the week.
Please consider staying in your current home, paying down your mortgage, and making improvements to it, until your financially "insured" that you cannot lose your home to foreclosure by gambling in the rental business. Also, read and study everything you can get your hands on about the real estate rental business and become more educated business-wise, or don't tackle real estate rental investment as a way to add to your financial assets.
having said all this, if you must have the other home, sell yours first!
All the best,