Family Law Questions? Ask a Family Lawyer Online.
Child support is always modifiable based upon a "change in circumstances". If your motion for a modification states that there is a "change of circumstances" you will at least get a modification of support hearing. At that hearing you will have to provide evidence of a "change of circumstances" -usually pay stubs, notice of termination, or some other documentation.
As to what is an appropriate child support order is pursuant to the child support guidelines.
Most certainly you will be entitled to get a hearing and then make your argument once his income in known as to what an appropriate child support order is.
As to the correct location to file for modification of support - the correct location is where the current order is in place. For there to be a change of jurisdiction - there has to be at least 6 months residency.