In your public_html add these two files:
.htaccess (if it's already there, simply download it and add into it the following)
#Activates php.ini config located in main folder to work also recursively for all subfolders, obviously replace your_cpanel_user with your full path, you find it in cPanel home page on the left it's called 'Home Directory'
upload_max_filesize = 64M
; post_max_size 8M (this might need to be adjusted too)
; memory_limit 128M (this might need to be adjusted too)
; max_input_time -1 (this might need to be adjusted too)
Actually 64M is really huge to upload on a server without using FTP, the other variables I wrote in php.ini file might need to be set properly to bigger values (I left them commented out using ';'), you can readmore in here: http://it.php.net/manual/en/features.file-upload.common-pitfalls.php