Does anyone upgrade for Darkfall 2.0 and how to do it www.cheapdarkfallgold.net

The web-site in your question is fairly self-explanatory. You're buying gold to use in the game. All you need to do is decide which package you want - and click the relevant 'buy now' button.
Looking around the site - it's similar to Travian - which I played a few years ago. On Travian, you could buy gold to use to enhance your character with things such as armour, tools, weapons etc.