How To Edit The Coupon Codes

[jimmyjazz]

I am looking for the file where I can edit the Coupon Code text.
What I want to do is remove the 'Apply Coupon' text & replace it with 'Apply Members Discount'
The 3 instances of text I want to edit are:

Apply Coupon Code
Apply Coupon
Apply Coupon

The last Apply Coupon text is in the button.

Where is the file I need to open to edit the above lines of text?
Or
In the case of the button;
Where is the image for the Apply Coupon button?

[abantecart]

There are many posts in the forum covering how to exit text in abantecart

Here is one as example:
http://forum.abantecart.com/index.php/topic,995.msg3775.html#msg3775