Change the text of table head in default view.

Hi there,
I am using node gallery module to work with albums and photos uploaded by user. While viewing the album there is a tab called Manage Photos which displays table with headings delete, Preview, Edit and cover. what I want to do is I want to change the text of 'Cover' as 'Album Cover', and want to display "Delete" column at the end. Please help me to do this.

Thanks for your time,
D-pak