Let's do a play-by-play of your proposal, shall we?
something needs to be done about people just going afk and making their team lose,
Consider the equipment and ISP the average player uses. If my internet is d/cing at any given moment in a match, my priority is on contacting my ISP to have it fixed. Although, if my internet is fine, and my PC can handle running league with little to no problems, and I decide to leave the match willy nilly, then yes under those circumstances should action be taken. Which it does.
I believe that if you go afk unless for ping problems and you cause on loss to your team you should be suspended for a week of play.
The Tribunal does suspend players for leaving a match after a certain period of time, if a pattern is noticeable. The end result is a loss accredited to all players on your team, including the ones who have left the match and issues a temporary ban for the player(s) who AFKed. Initially, it's 1 day. Then 2 days. Then 3. Then a week, then 2 weeks....you get the idea.
I think this is fair because it will really cut down on trolls ruining perfectly fun games that should have been won.
Naturally, yes. But wouldn't it be worse to force players to stay in a match against their will? By this, I'm not condoning trolling by AFK, but rather stating it happens for a reason; players may not be having fun in matches and want to exercise their right to leave, or the situation cannot be helped from a technical standpoint.
It has gotten really out of hand and the worst part is there is nothing we as players can do about it to help the game.
Well, not so. Reporting the player for AFK is the most immediate solution. Understanding the other reasons for it, besides intentionally trolling, is the long-term solution. Granted, you might not have another AFK in the next match you head into.
Everytime someone in my match d/cs, or is in the match long enough to state they have ping issues, etc. I don't throw my hands up. If they don't return immediately, I wait it out. If they don't return >25 min mark and we lose, so what? That's the reality. I go into another match and expect the unexpected. One or two (or even the rest of my team) leaving a match, for whatever reason, isn't enough for me to complain. That's counterproductive.
Riot cannot force players to play the game, or even stay in one. You make those choices. As such, understanding it's a given right will, hopefully, put perspective on your team member that happens to AFK next time.
Sorry for the wall of text. Had a lot on my mind about this.
and will still lost because the other teams 
got a free top lane and farmed and just took the turrets. Then after first turret they pretty much one they game even though I was 15/4 after 20 min, then we got crushed so I feel you and these games just happen sometimes and it sucks.