Sounds like you have more issues than just a head gasket. For the turn signals, check a fuse where ever the box is and see if its not blown. or the actual switch might have gone out. For the radio, you might just have a lose wire in the back. Transmission...you might just have to replace. Honestly, hate to say it, this car sounds like its not worth fixing. i would sell it to a mechanic or start off parts cause this thing might start running up a nice bill since you are unsure about how to fix it.