My 3gs has crushed when trying to downgrade .. plz help :(

[Evane$cencE]

guys i have my iphone 3gs .. it was in 4.3 ... then wanted to downgrade ..
i have downgraded to 4.2.1, then " connect to itunes " appeared, then i used recboot, but it stayed rebooting the showing " connect to itunes "
i jailbreaked it by greenpoison, nothing occurs, then redsn0w by using firmware 4.2.1 and installing cydia only, the device worked, but with " no sevice ... noticing that it's unlocked originally, then i made reset for all settengs and data .. then it stuck in the "connect to itunes" screen .. now i can't install 4.3 , 4.2.1 and even the 3.1.3
what can i do :S

[iPittsburgh]

Download tiny umbrella from The Firmware Umbrella - TinyUmbrella and try to exit recovery.