product images and add to cart graphic

I would like to change two things on my site:
a) I have two images for each product and my product is currently displaying as two thumnails and the main image. The problem is the main image is the same size as the two thumnails underneath the main image. How can I change the main image so that it is larger than the thumnails? See www.african-brand.com , click on any categoty listing and display a selected product to see what I mean. An example is on this link www.african-brand.com/index.php?option=c...category_pathway=552

b)How can I rationalise the link I provided in one above? Ideally I would like it to just show as www.african-brand.com/index.php?{categor...b-Category}/{product }
e.g. www.african-brand.com/index.php ? {Music}/{South African}/{weding-specials-vol3-no-one-is-perfect}?

c) If you have visted the site above you would have seen that the add to cart graphic if I may call it that is very lame. How can I use the one on your demo site or other?

Thanks in advance

"b/ You should turn on SEF in the joomla configuration. Then, in the configuration of HikaShop, there are some parameters in order to configure the way your SEF links will be generated."

I have done this assuming the parameneters you are talking about are the four configuration issues under Hikashop>>Configuration>>Main>>SEF url options. There was no improvement after changing to the following configuration:
Simplified breadcrumbs: No
Activate smaller url: Yes
Category SEF name: category
Product SEF name: product
Is there somewhere else I should be looking at?

"c/ The add to cart button uses the CSS of buttons of your template. Your template apparently doesn't define any CSS for buttons, that's why it's displaying as a normal button."
I use the css you supplied. I think you gabe me the wrong css. Look again on your demo website you see the add to cart styling with the colour change on hovering on +/- for cart and the blue basket icon. Thats the styling I am looking for. Could you re-send the styling?

Lastly, if you take a look at the hikashop category listing menu on www.african-brand.com i.e. "our store", after changing settings for css on Hikashop>>Configuration>>Display>>CSS>>Front-end CSS File to "default" the menu intems are not aligned to the right as one would expect. which Css settings should I change? Wonder if you could give me the css used on the dem site as well, might use an altered version of that.