Can I make a header at the top of my Nexgen gallery?

I currently am using the Atahualpa theme in WordPress. I got a good header set up. Then I installed Nexgen Gallery. Now things are getting confusing again. Do I have too many addons? I am having trouble learning what does enough on its own and what needs another addon. In other words, I have WordPress. I wanted to have a better header then the regular WordPress themes and I found that Atahaulpa allows me to customize my header. Then I installed Nexgen Gallery and now I am getting confused. I am still not done adding stuff because after I get these looking good I will need to install Eshop so I can sell the items in my gallery.

So now I’m thinking that I should remove Atahaulpa and just use Nexgen and worry about dressing it up later. Also, I wonder is Eshop will suppy me with its own gallery and will it be adequete and so I would not need Nexgen.

I’m wondering if I am up to this.
Can someone offer some guidance? I am wanting a store to display and sell photos. I want it to look respectable. Not really interested in a blog, just a webpage.