Hi,
I just had a very quick glance at your site, and the first thing I noticed is that you are not using your <title> tags effectively, which are quite (if not very) important in how the search engines rank you. There's no title at all for your home page, for example, and very minimal titles for internal category pages. You'll need to address this if you want to generate visits through natural search.
Looking at the site, it appears to have been well designed. It's very easy to use, the layout is clean and uncluttered, the navigation is intuitive, and any random link I clicked loaded the page quickly. Your web designers have done a fine job, I'd say.
However, I've no idea how the E-commerce end of it works, but I'd imagine that the designers have tested it properly. The best thing you can do is to put yourself in the shoes (or fingertips, as it were) of a potential customer and work your way through the buying process, trying out as many variables as possible to see how it works - and where it doesn't.
As for the browser to buyer ratios; these can vary drastically depending on what kind of products are being sold, how competitive the market is, and whether a site has significant savings to offer. In the case of your own site, most visitors will be looking for something in particular, and if you have the product they want at a competitive price you should have a decent ratio. Compare this to, say, Amazon where many visitors may be simply browsing. I doubt you'll have too many people browsing through a page full of drill bits, for example. Someone who has reached the drill bits page will probably be looking to buy drill bits.
Your immediate problem will be generating the traffic. I imagine that you have already incorporated your new site's url into all your existing media. By this I mean you should already have the website name and url visible on your advertising, on your letterheads and envelopes, etc., your delivery vans, and every other single piece of off-line media that you use. You'll no doubt have already looked into using paid advertising on the web, which means of course Google adwords. You'll need to study up on PPC campaign management, or hire someone who knows this inside-out.
While I'm on the subject of Google Adwords: it's worth signing up to this even if you don't end up using the adwords platform, if only to have access to the free google analytics. This will require your webmaster installing a very small piece of code, but it will give some very good data on how your site is being found, and the keywords that were used to find it.
But first, sort out your meta tags! Because of the very specific nature of your business the keyword research for your pages will be self evident. You may want to include the manufacturer names on pages where their products are displayed. For example the page on SDS-max drill bits should have "Ruko" in the page title.
Hope this helps.