Need Advice Regarding Negotiating Seller Financing on a Deal

[Jeffrey Clark]

Dear All,

This is my first post and I could use the advice and guidance of those with more experience in the matters.

Situation: I am currently leasing a commercial space to start a healthcare practice. The unit is 3700 sq/ft and has two medical suites, mine and an adjoining suite that is currently being leased on a month-to-month basis. The facility is for sale and the seller has given me the right of first refusal to purchase the property, although we have not been certain if we want to purchase the building. I have just spent about $100k on a new remodel of my space and increased the value of the building. I'm interested in seller financing, but can obtain bank financing. The building is owned outright by the owner and I have a good relationship with the building owner.

Question: I am much more interested in acquiring the building now, but am interested more in negotiating seller financing, if possible. How could I negotiate a fair purchase price for the building for me, given that I just spent $100k on improvements? The building price was $325k before I remodeled. What would be a fair price and how do you recommend I try to negotiate that price? 

Thank you in advance for your feedback? I understand that these negotiations should have taken place before I spent $100k on improvements.