Adding translucency to bootstrap navigation bars and photos, and increasing font sizes

I've looked at many posts on StackOverflow and other websites, but I just can't seem to figure out how to make my navbar in bootstrap translucent. I don't want the words in the navbar to be translucent, but I want just the navbar to be. I also want to apply an opacity to the background picture. I also want to increase the size of the "My App" text without changing the size of the links.

Heres my code:

http://goo.gl/P8jpgG