I don't quite understand your logic. You say in one statement that your a mediocre player, then you seem to hint your a good player. I think that your obviously not enjoying the game at the moment because your losing money.
If you feel that poker is not for you, then fine at least you gave it a shot. If on the other hand you enjoy the game, then you really need to come back with a plan. If you think by depositing a $100 next week and thinking that by the end of April you'll have $1000, then you are seriously deluding yourself. Sure it can happen, but for the majority of us we have to grind it out and build our bankrolls over a long period of time and over 1000's of SNG's or 100,000's of cash game hands.
Also to think of poker in terms of consistency ie, 'if I'm a good player then if I play 10 sng's I should be able to cash in 4 of them' well again thinking like this is wrong. You see, poker is not particularly consistent over a small period of time. There are pro SNG players who earn $100,000's of dollars a year and can have 1000 game streaks with break even stats. Regular cash game winners can go on 50k hands downswings.
You need to play with a
bankroll that is more than sufficient for the stakes you play at. This must not be understated, it's so important to becoming a successful player. Read, read and read some more, you may think you know how to play, but seriously you don't. Never think you know it all, always be prepared to improve.
Anyways I've gone on too much, if you need some more info PM me. GL.