Champions to climb from silver ASAP.

Hello. Just played placements and landed in Silver IV (so meh) thanks to a 3/7 streak. I was Gold V last season and I would like to continue it with at least Gold. So I'm looking for few champions on mid. I mained Karthus/TF/Fizz but I lost faith in my skills with playing last two ones after placements (well I wasn't able to carry). And playing Fizz is soooo damn boring for me. And Karthus doesn't seems that good champion to get out from silver. So I'm looking for new possibilities. I was wondering between new midder or jungler. I thought that Viktor and Swain could be quite successful to climb out - I didn never see losing Viktor against another midder in bronze/silver. Swain was a pick, because he can get a really huge sustain and he's really good at annoying/outfarming and he's got low popularity, so that's a key - nobody knows how to play against him. With junglers I was wondering between Jarvan and Shyv. I was playing a lot with Jarvan when he was at rotation and I was playing quite good. Other way with Shyv, but I haven't played her for a long time - but I see that's she is really good now. I was also thinking about Jinx. I'm not that good adc, but if I could train her I would climb much higher.

I'm waiting for your propositions.

PS: Yeah yeah I know "Play what you play best" etc. However I haven't masteried any champ even (I was playing more only with Karthus/Kassadin, however after Kassadin's nerfs years or two ago I stopped playing him, he was so bad).