Hey again,
Congrats for the tournament result! Well done! 
Depositing funds will enable you to register a payment method in order to request a withdrawal. No biggie.
However, the $50 winnings would not qualify for the rake amount you need to reach. Its not how much you won but how much you played/raked. You understand?
So, for example you'll get 5 StrategyPoints for every $1 rake you produce. All you need to do is check how many StrategyPoints you have in total from Poker770 and divide it by 5 and voila, you have how much you raked so far. Please note that Bonus StrategyPoints won't count towards clearing bonus.
I've sent you a ticket where I've made the calculation for you just in case you wouldn't know how to start. 
I hope this helps.
Ingrid