Getting WP-db error

I use Word press 2.7

I get this error when i click posts or try to submit any new entry

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 71 bytes) in /home/narayan/public_html/arthaguru.com/wp-includes/wp-db.php on line 808

My site http://www.arthaguru.com/

Please help and when i try to auto upgrade any plugin it says

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 170057 bytes) in /home/narayan/public_html/arthaguru.com/wp-includes/http.php on line 1032

What shall i do please HELP HELP