server overload, site suspeneded

Hi,

My website running on wordpress has been suspended a lot of times by the hosting company. They are warning me that this is the last time that they will tolerate a server overload. Nevertheless they suspended the domain. I would like to find out what is causing this suspension. The website has about 1200 posts, each post has about 6 pictures on average. There is a maximum of 10 to 20 unique visitors a day, very low. These are my plugins:

– locat avatar
– akismet
– all in one seo pack
– author avatars
– bm custom login
– get recent commentes
– global translator
– google analytics for wordpress
– gt cache
– limit login attempts
– pagemash
– query-posts
– random image selector
– random post link
– register plug
– tweet old posts
– twitter tools
– w3 total cache
– wp db backup
– wp d tree

The domain is http://www.artglassleiden.nl The site is currently suspended because I do not want to risk another suspension, or possibly a ban. The theme I am running is The Gazette Edition from Woo Themes http://www.woothemes.com/2008/02/gazette

Can you please identify what might be causing the overload? I have the most recent version of WordPress and the most recent plugin versions. The last overload was this morning, the previous one in February. So it does not happen all the time.