Header Margin and Logo Size

I am new to WordPress so please bear with me whilst I find my feet. After finding many useful posts and searching through the .CSS files I still can not seem to rectify my problem sorry.

I am having issues with the header logo size and also the margin between the logo and the image slider on my homepage:

http://www.rnrforyou.co.uk

Ideally I would like to increase the size of the logo and move its position to the left.

I would also like to keep the black header the same size but decrease the distance between the logo and the image slider.

I would be grateful for any assistance as I am now at a complete loss.

Many thanks.