在bootstrap安装MVC 4后无法整理登录页面

I have a standard login page on mvc 4 which is functioning fine but my html knowledge is very weak and I need a quick answer to tidying up the form after I installed twitter bootstrap, the username and password labels are stuck on the same line within the form, can someone please recommend a quick fix to tidying up my code, Thanks I have a standard login page on mvc 4 which is