how can separate a part to two part

Unfortunately with Solidworks you will not be able to separate each part. The piece imported as one part. You could try feature recognition to show the individual bodies in the part. The only way I know to separate this is to trace and draw each part in and assembly.

Perfect application for the Split command.
With sketches, planes, or surfaces, you can split the model into multiple bodies.

Check out the help file. I think there is a good example of splitting up a wrought iron fence in there.

Now that you've split the part into multiple bodies, look in the feature tree. You should have a Solid Bodies entry with a count of the bodies.
Right click on the Solid Bodies feature tree entry
Choose the Save Bodies option.

I like to rename each body in the feature tree before doing this, but you can also rename the bodies as they are being saved. Or you can just leave them with their (useless) default names.

There is a little checkbox in the save dialog as well which will allow the automatic creation of an assembly (in case that is your next step).