Sorry to dash any of your dreams, or anything, but I'm gonna have to say that Steam Calc is probably one of the least trustworthy sites on the internet when trying to back up selling a steam account.
First of all, it calculates your Steam acc value based on if you bought every steam game full price, one by one, priced on day of release. Sadly, the internet does not work like that.
Noone will pay even CLOSE to full price for anything. I sold a $1200 steam account, and it fetched barely 50-60 dollars. It had all the CoDs, Arma II, over 70 Steam indie titles, each priced at 10-20 etc. The $1200-$1300 price was from Steam Calc.
Also, the games in this account are, let's say, not 'valuable'. This means there is a tiny demand for any of these games. Not trying to insult you, but 300 dollars is IMPOSSIBLE. Anything over 100 dollars is IMPOSSIBLE. A reasonable sum for this account would be $30 MAX.
I apologize, but this is the only way Steam accs are sold.