Changes to CSS and Wordpress Theme File

http://www.honesttraders.co.uk/services/

1) In search bar change - 'Search keyword' to 'Type Company Name or Town'
2) In search bar change 'Category' to 'Trade or Service'
3) Let me know which file or how I edit the above in future if I need to change these again on my own.
4) In top menu, change colour scheme of the 'TRADES APPLY HERE BUTTON' but all other buttons remain as they are.

- button background: #3e6f4c text: white (for default state and when on that page)

on hover: background #39613e text: white

Please make this change in the custom.css file which is in public_html/services/wp-content/themes/businessfinder2/custom.css

If you are interested in this small job let me know,

Thanks,

Scott : )