unclear re: rights issue

Sorry guys, but I am still very confussed with regards to this rights issue thingo. I have been trading for quite a while but I'm struggling to 'get' this one. I own TAM shares that are most definately at a loss now. I read about trading new issues now but how can we if they aren't paid for? Also, what's to say this won't go lower judging by current performance and technicals. I really don't see the value of spending 20c/share on new shares. With the recent drop I can't see the sense in buying more and hoping that it will go back up a lot to try and get my inital money back. I might be incorrect here but at 20c then selling at say 25c, I am still a very long way down the gurgler. I wonder if I might be better just to sell current holding for a tax loss and move on.