Advice on what next

[Ryan Burns]

Ladies and Gents thank you so much for your time. A little about myself and my situation. I have a solid job I'm respected at and make about $75,000 a year working six days a week. I was able to buy a duplex in Lowell, MA with FHA financing for 245,000 and my gross rent from the side I do not occupy is $14,400. I have spent the last 6 months fixing the house to suit the needs of myself and my wonderful girlfriend. I view real estate as the way I will make my fortune and I'm wondering, what next?
I've read more than a few books on the subject and my current strategies I'm considering are using my 401K to buy a 2/3 family to fix up and hold or using hard money to buy a larger 4 br (or convert a 3br) home with hard money, fix up, mortgage with 70% LTV to cover hard money, and rent to section 8.
I'm currently putting my gf through school for another 6 months, during which I plan to read more dilligently and formulate my plan more fully. I suppose my rear problem as I see it is financing a property purchase and a rehab so I can refi the cash out of it needed to get the next house. I plan to study appraisal and inspection procedures so I can know what to expect in rehab costs and returns. Any advised reading or course of action truly is appreciated. Thanks!
Ryan