How to get larger version of author avatar

I found the function that makes up bp_post_author_avatar() and then changed the type to full. Place this funtion in functions.php and use the new function to call the post author avatar in the template.

function fod_post_author_avatar() {
global $post;

if ( function_exists('bp_core_fetch_avatar') ) {
    echo apply_filters( 'bp_post_author_avatar', bp_core_fetch_avatar( array( 'item_id' => $post->post_author, 'type' => 'full' ) ) );  
} else if ( function_exists('get_avatar') ) {
    get_avatar();
}
}