Adding Search To Nav

Hi.

I really enjoy the simple shop theme and will most certainly be purchasing the pro version when the time is right, during development of free theme I have noticed there is know search available anymore. I have a plugin which displays a search, but as a widget so I can’t have it at the top of the page like normal search is, how can one put the search plugin into the nav bar or at the top of the page so it works at the top. Many thanks