I get a low reverse /postion on a 2000 dodge stratus what should i do

SOURCE: 2000 dodge stratus rear end suspension diagram

Diagram

SOURCE: 1996 dodge stratus The shifter

Try shifting into Neutral and attempt to Start the car.
If this works, there is probably a problem with the cable and/or cable connection/shifting bracket to the transmission.
When shifting, is the Indicator "on" or to the left or right of the appropriate selection (PRNDL)? If the indicator is to the left or right of them there is a good possibility that you need to loosen the gear cable connection, located on top of the transmission and pull the shifting bracket going into the transmission - towards the front of the car. While holding the bracket to the front (Park) position tighten back down the cable fasteners. Before doing this, inspect that area to ensure nothing is impeding the cable/cable connection/shifting bracket, or interfering their operation.

SOURCE: is the ecm computer in a 2000 dodge stratus

No it is not. To get compatible ECM's the manufacterers part numbers have to match. Then you have a 1 in 1000 chance that you can hook it up and it runs all the components. Which means that it will have to be reprogrammed to your car. The VIN number is what it is programmed to..

SOURCE: Where's the battery on the 2000 dodge stratus

Hi,
The battery is located in the inside left front wheel well behind a protective shield.

SOURCE: 2000 DODGE STRATUS. OIL LIGHT

I would have the oil pressure checked with a pressure gauge. Most likely you have low oil pressure. Not much you can do about this problem now. A used engine swap is probably the cheapest answer. Have it checked before buying an engine. Could have a bad wire or plug at the sending unit.