got error after activated the plugin

i got error when i just activated market press plugin and now i cant enter my admin dashbord

this is my site
http://www.pyrmont-restaurants.com.au/

i got this error
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 122880 bytes) in /home/tradesme/public_html/pyrmont-restaurants.com.au/wp-admin/menu.php on line 81

Thanks