WPMU site upload limit

I have WPMU installed, on one of the sites I need the upload max limit to be 5MB as opposed to the current 2MB.

What I have done so far:
1) Made an edit to the site (Networks Admin --> Sites --> Selected site Edit --> Settings --> Site Upload Space Quota) to allow: 5500

2) Added define('WP_MEMORY_LIMIT', '64M'); to the wp-config.php file

3) Made an edit to the Network Setting (Networks Admin --> Max upload file size: 5500)

After all of the above, I am still restricted to 2MB of upload file size.

Please advise...