1995 Lexus ES 300 Instrument light and O/D off

Hi. All,
I just bought a 1995 Lexus ES 300. It has 179,000 miles on it. It drives very well and passed the safty inspection, but the instrument panel light is off. So I can't see the engine collant temperature gauge, the tachometer, and fuel gauge, esp. at night. The needles for the engine collant temperature gauge and the fuel gauge still light though the one for fuel is sometimes twinkling, but the needls for the tach are off. I wonder if you know how much it will cost to fix these.

Also, the user mannual says that we should "Always set the overdive switch to the ON position to improve fuel economy and quiet practice" , but the indicator light on my car says "OFF" and when I set it to ON, the O/D OFF flashes. However, the transmission doesn't seem to be a problem since it shifts very well and there's no delay. Could you tell me what the problem is? Do I have to go to a Lexus dealer now? Thank you very much!