How to i change the tour serach function on the home page

Good morning i required to change a few things inside the tour serach please have a look on the home page
http://www.holidaycorp.co.za you see the serach function on the top on the home page just under the video.
I need to change word phrases such as tour name to holiday name , tour type to holiday type search tour to search holiday (button)
Please tell me how ica make these changes
thank you