There will be an option in the next release to do that, but it will require the X-Plus plugin.
But in your case, if I were doing that, would either use the Header Widget Area, putting the logo in one widget, and the title/tagline in another using the shortcodes [site_title] and [site_tagline].
OR
Probably the easiest solution of all, and I really don’t know why most people just don’t do this, is use a photo editor and combine the logo and the other text onto the same image. Then you get complete control of placement, fonts, colors – everything, and you end up with a header that looks just like you want.