1. The quantum of maintenance is determined on the basis of your present salary. So if your income is 25K then produce the proof in support hereof and seek revision on amount of maintenance.
2. You can wait till she files execution case for recovery of the arrears maintenance.
3. Ask the court to dispose of the interlocutory petition u/s 21 of the Act. unless all interim petitions are disposed of the court can not proceed with the trial of the suit.
4. The falsity or acquittal in 498A case has nothing to do with the merit of the maintenance case. if your wife is without income then your liability to maintain her subsists.
5. The lie of the witnesses has to be made apparent during their cross examination. If you can not establish their lie the court would believe them to be true.