Display Image logo along with site slogan and site name
I would recommend to use the "Panels" module to do that. Create a "mini-panel" and while editing one of it's panes (boxes of content) choose on the edit menu "Page elements" and then add "Logo, "Site name", and "Site slogan" respectively. Make sure you arrange them as your liking.

The second part of your work is to do some CSS for this. The Panels css system takes some time to learn --- You should use DOM tags carefully to isolate the Id's and classes of the right div's and manipulate them in relation to their upper div's, but it's worth the shot.

If your site is responsive you should add some responsiveness with a Media query, i.e:

@media screen and (max-width:519px) {#panel-col-first {width:100%;} #panel-col-last {width: 100%;}}


In Panels, make sure that after you choose basic details and layout you navigate in "content" tab. Then, Add the aforementioned details - Here is a screen that'll show you how: