Negotiating A Lease w/ Pre-Existing Tenant in Commerical Property

[Dewain J.]

Hello All, 

I'm a new investor and I recently acquired a property that has a commercial 1st floor and several apartments in it as well. The apartments were all in need of rehab and are vacant. The commercial space is occupied by a business operating on a month to month lease. 

To acquire the property I used a mix of my own cash and a hard money loan, so I do have some interest payments being made monthly, so having the business in there to offset some of that expense has been great, but I think that their rent is a little low for the space they have. 

As the rehab is coming to a close and we are looking to start filling the apartments, I need to address the lease situation with the business tenant. They have been operating on a month to month lease all along with the previous owner, and we just let it continue while we rehabbed. Obviously we'll need to sure that up for a longer term. Also I feel the rent may be too low and would like to increase it, especially since we had some capital expenditures that had to go into this space already. 

So I just have a couple questions. Any help would be appreciated. 

1. How can I go about finding out what the market rent  for the commercial space should be for the area? 
2. Any advice on approach in terms of addressing an increase in rent? They seem to be good tenants (they had even put some work improvements in the place themselves prior to my purchase), and I would love to keep them there and not have to deal with a potential commercial vacancy. 
3. How long of a lease should I shoot for, and is it normal to build incremental increases?