Wordpress Theme matching my website

I need a very simple wordpress theme matching the design of my existing website. The header can be included with a simple php include with an existing file (header of existing website). I need a left sidebar showing the 50 latest posts, search function and tag cloud. The posts should only show the headline and the content. No other information like date, author, category, tags, comments, etc. So it´s very plain and simple. I will only use posts, no sites. Also comments will be deactivated - so there´s no need to care about those things in the theme. Please contact me for the link to the existing website to get an idea what it looks like (it´s a very simple design) and a psd what the Wordpress-Site should look like.