Button colour change & how to centre content in sidebar

Hi guys, love playing with this theme. Its my first attempt at using wordpress and customising a theme and I’ve built this in the last 2 days http://203.79f.myftpupload.com Is there a way I can change the colour of the submit button on my home page – I’m trying to change it to #A16f3c Also, I have put a calendar/events widget into my Optional Sidebar 1 on my Visit Us page. Is there a way I can centre the widget content within the Sidebar ? Many Thanks Ian