Marketpress Add to Cart Button Changes

I have a few custom changes I want to make to Marketpress.

1. If a user is not logged in, I want the Add to Cart button to change to "Login to buy" or something similar? Is this an easy fix?

2. I have

<?php_e( 'Items in Cart:', freemarketers ) ?> <span><?php echo sprintf(__('%s item(s)', freemarketers ), mp_items_count_in_cart());?>

in my header to display the amount of items in my cart, however I only want this to be displayed when there is 1 or more items in the cart, not when there are zero.

Thank you so much!