Investors will still want to have your company funded before funding it. So the money you would spend in a 3-months postdoc is probably best spend already investing in your company.
BecauseOr towards funding some research to get your innovation patented.
Since it is your company, if you are smart in the way you put the money in the company and you do not spend them, you may evenwill recoup a large part of them quite soon.