Firstly, I've faced this issue before where my "menu container" was not in the right place, look at the screenshot I've attached and play about in that menu to see if you can bring it back into line with the text at the bottom. "Menu Container -> Margin"
Secondly, regarding your slider I THINK you'll need the "Premium" plan in order to add custom HTML and CSS, that being said a image/video slider (based off the Nivo Slider) is available to use with iClan - I'd imagine it would also be available for those who are on the free plan too.
**I once tried adding a slider to my website (Sliderwall) and I drank more coffee's then I could handle and finally gave up after 8 hours of trying, I envy those who can install these sliders in under 5 minutes...they make it look simple! xD This is attachment