In skins mainly vb is CSS & html. You can use Dreamweaver to create the HTMl you what for your skin and then input it in th proper place in teh templates of your vb skin. IF you are able to do graphics, html & css you have a really good bet of getting something close to the way you want it on your forum. Looking at the design it actually would not be very hard to code it into the skin. The main template you would need to look at would be the header template & FORUMHOME. You can put standard html in the templates such as tables and what have you to hold your images where you want them, or you can use CSS to do this, whichever you are more comfy with
As for the cost, that realy always depends on each individual designer adn what they charge for certain things. Some are better at other things then others and some charge more if they feel it will be alot of work involved in the job. It just depends on who you get and how they work things.

I've seen many designers really charge alot for some things and I've seen them IMO not charge enough for others, so its all personal really in the end. Since you do have experience in adobe photoshop I suggest you make your graphics with it and then implement them or code them into your skin you can't go wrong with this approach at all. Good luck
MP