Any advice on making this deal happen

[Jeremy Namen]

I want to purchase a building for my construction company. Ive been in business for about 10 years, formed my LLC in 2005. I currently have my office at home and i feel that this is limiting my capabilities. I want to separate my work life from my home life (or at least dramatically limit my work at home). I also want to represent my business more legitmate and Id like a space that customers as well as other contractors can meet me and plan projects. I found a recent listing in my primary area of focus and only 2 blocks from my home. The place has everything im looking for and more. It includes 3 apts that will rent easily and pay for all my expenses. Its listed at 75k- The seller is out of state and owns a large asphalt corporation. My only concern is that i probably wont be a ble to get a residential loan ( i will find out next week) and ill have to come up with nearly 20k for dP. I can come up with 5% fairly easy whenever, but 15k-20k will take up to 6 months to gather. Should i try and get owner to finance for a year? offer to close in 6 months ? I want to get a contract but im not sure what my realistic chances are- any thoughts are greatly appreciated!
Also to add i currently have 5 rental props in my LLC all under 1 commercial loan...This particular bank has held off on most commercial loans for now.They prob wont be able to do anything for months im hearing. one of these rentals is my residence, i rent the other side. and these are my only loans. It is going to be tricky to separate these loans, but i need to start that now as well--any thoughts are greatly appreciated!
Jeremy