Want to raise low rents , how and how much

[Tom Server]

Hello BP, I'm currently in the process of purchasing a triplex. Offer accepted.

 Doing the numbers my net cash flow should be between $500- $700 a month with the current low rents. 

Im in New Jersey and the current rents are really low, but the area isn't the greatest. 

Current rents are 

2br/1 bath-$1050 

1br/1 bath-$ 950 (section 8)

back apartment-

2br/1 above a 3 car garage $1050

The 3 car garage is also being used for storage, I believe from all 3 tenants 

All tenants have been there for a while, all over 5 years and lease right now are month to month

I was looking at the Hud websites for the area and the FMV rent for a 2br 1 bath is $1471 and for a 1br 1bad $1140

Any suggestions on what to do.. I also would like to charge for the 3 car garage use, or have them remove their stuff, so i could store my personal stuff in there and save me 200 dollars a month for my current storage unit. 

 Thanks