1993 Lexus LS 400 Short circuit / dash board flickering / o

1)Six months ago, my dashboard lights flicker on and off constantly sometimes the dash goes completely black is this an electrical problem and can you tell me an estimate charge to repair this problem.
2)About 2 weeks ago, my overdrive on/off indicator light on the dash board won't turn off even when I mannually switch the overdrive switch to off.
3)The rear signal light indicator on the dash board won't turn off.
4) My Delco battery is now dead and can't be charged because of "Bad Battery".

Are these electrical problems and what are your best suggestions? Where can I fix these problems? Is it worth to fix this junky / old car?

Many Thanks.