Hello,
Thank you for choosing our theme!
1) Go to Theme Options > Header builder > Menu > choose the font-family you need http://prntscr.com/u13w3k
2) Edit the border width and color at the same place http://prntscr.com/u13wjz
3) It depends on the element you used there and what exactly you want to change: color, font-family, or font-size?
Regards