I have the property under contract and will be closing with cash, I then hope to execute the additional transaction (sale from me to end buyer for the higher price), both transactions will be at same title company; double close.

When you get into adjusting for square feet thing get a little more complicated when you look at values for the marginal (read: additional) sq ft.  

Contact local community banks in addition to the credit unions to find a lender to do the Refinancing.  

Additionally, I have a lot of clients that are private money lenders if you are ever in need of financing.

If you cannot convert it into really useable space, what if you split it in half and put coin op washer/dryers on one side for your tenants use, and on the other side, put storage areas that tenants can rent for an additional fee.

For all you Dave Ramsey acolytes out there I invest in real estate now because without additional income my ability to pay off my student loans at my current salary (which is a good salary) plus living expenses etc... would mean not be able to pay back those loans and be debt free for at least ten and maybe 15 or 20 years down the road.

My question is would it be possible to get another HELOC, or home equity loan, etc. for an additional 30%-40% possibly?

Can you post any additional details about your deal? 

I'd say that after the job is completed, I might need to revisit the project to make additional minor repairs to the garage, and the money is intended also for electricity needed for the minor repairs, if they ever come up. 

(Sorry for the additional questions, but I know I would have these questions in my sleep.)