You should be able to find the original "Add to Cart" button here:
/app/design/frontend/base/default/template/catalog/product/view/addtocart.phtml
Copy this file into the corresponding place in your theme, eg:
/app/design/frontend/PACKAGE/THEME/template/catalog/product/view/addtocart.phtml
(You might find this file is already there.)
Then we need to add this file back into the product page. This is done with this two stage process:
First edit your local.xml file, which you should find here:
/app/design/frontend/PACKAGE/THEME/layout/local.xml
And add the following to it:
<reference name="product.info">
<block type="catalog/product_view" name="product.info.addtocart" as="addtocart" template="catalog/product/view/addtocart.phtml"/>
</reference>
Then open up your product view page, which you should find here:
/app/design/frontend/PACKAGE/THEME/template/catalog/product/view.phtml
And add the follow code to it, where you want the add to cart button to appear:
<?php echo $this->getChildHtml('product.info.addtocart'); ?>
That should get you your add to cart button back. All of this is assuming your version of Magento hasnt been altered too much from its defaults.
As for changing the prices, this can be done in the Admin Panel. If you would rather change the prices in a spreadsheet, then go to System > Import / Export > Export to generate a CSV file that can be opened in something like OpenOffice. Then you can use the same system to import the CSV file without having to install an extension.
HTH
Enquire Now >(the button text), and nothing was found. Odd. There are about 963 products. – Steve Nov 13 '15 at 16:03Enquire Now >. I needed to search forEnquire Now >. Customisation was inapp\design\frontend\default\modern\template\catalog\product\view.phtmlas you said. – Steve Nov 13 '15 at 16:16