Choose Options button text

I've been putting some reguired options in place for products which changes the 'Add To Cart' button on the Category page to 'Choose Options' which takes them to the product page.
I want to change the text of that button to 'Choose Quantity'. I'm not great with php but I've looked in all the language files and tpl files to no avail. Anybody know if its possible?

Got it! Its been over a year since I first set this site up and I forgot I'd used an 'Live Price' options display extension! So I found the Language file with 'Choose Options' in the Vqmod folder