Can an employer eliminate a position, terminate the person in that position then create new positions to do the work she is doing?

Very generally yes, employers can terminate employees, create new positions and assign duties among various positions.  There's something assumed in your question though -- were you wrongfully terminated?  Why do you think what happened was wrongful?  Pennsylvania is an employment at will state -- meaning your employer can generally fire you without cause.  There are certain situations where termination might be wrongful.  For example, if you have a contract and the termination violates the terms of the contract.  Or when the termination is the result of unlawful discrimination.  it would be helpful for you to provide more specifics about your situation.