An Affiliate Setup for an E-Shop

Hi everyone, first post here.

I'm a business owner with a small e-commerce business. I've very recently gotten into the affiliate game. I sell high end products and I've signed on a few specific affiliates because I'm kind of in a niche industry. The numbre of affiliates will probably be something like 3-5.

I need to be able to track affiliate links and comissions. My requirements are that affiliates have their own unique URL that they can append to any page or product page on my website and then have the tracker track the affiliate link. Ideally, the tracking software would be implemented to our cart so that when a checkout event happens, the affiliate is credited. I would also like the URL links to be short for example; www.example.com/*product*?*affiliatecode*. It would also be nice to be able to record direct linking through the affiliate's domain.

I've taken a look at the self hosted apps like Post Affiliate Pro, iDevAffiliate I was wondering how the marketing gurus here do this? Is there a better way of doing this? We also have analytics software that we can create a campaign with I guess and track a keyword or something but it doesn't really do the rest of the features that I'm looking for.

I'd appreciate any advice you guys could give me