Help requested for with timer circuit

[Spacial]

Be really grateful for any suggestion of how to resolve this problem:

[img]http://i62.tinypic.com/2qd4l51.jpg[/img]

[pebe]

Put a 4.7K resistor across the 12V pulse input. When the pulse has ended, the cap will then discharge through the 10K and 4.7K resistors in series, in about 1.5 secs.