You can achieve ".html" after each url by below instruction:
Go to System -> Configuration -> Catalog -> Search Engine
Optimizations and modifying Product URL Suffix and Category URL Suffix
respectively.
But for your above request for change url from "mysite.com/store.html?manufacturer=107" to "mysite.com/nameofmanufacturer.html" , It seems you are trying to open category and filter manufacturer attribute. But its not possible.
You can do 1 thing which is better as per my suggestion:
Create category with "nameofmanufacturer" then you will get category url "nameofmanufacturer.html". NO need to include this category in MENU if you want. Also after this you can use "REWRITE URL" for redirect from "mysite.com/store.html?manufacturer=107" to "mysite.com/nameofmanufacturer.html". Hope this will help you. :)
.htaccess
rerwrites -> rewrite info: addedbytes.com/blog/url-rewriting-for-beginners [check the part aboutparrots/norwegian-blue/
fromget_product_by_name.php?product_name=norwegian-blue