simplo header logo

Can anyone help me with tweaking a header to get the logo to display correctly. I Have a website called http://www.giggleselc.com.au the template is from http://wordpress.site5.net/simplo/

I have an image which is larger then the simplo demo image and seems to overlap with the menu. Could anyone tell me what to change so it does not overlap

I’m no css guru so would thankful for some help