You would need to meet with an experienced family law attorney to try to get above guideline child support. You are in Harris County and if you can establish what the judge would want to see, you have a chance of getting more than the standard formula child support. Look on this website and find an attorney that has handled a case like this before. Good luck!
The standard you are going to be fighting against is a material and substantial change in circumstances. While there are certainly more facts than the general description you have set out above, you should keep in mind it is a relatively high burden to overcome in showing materiality; also that the father, while absentee, is still meeting his child support obligations on time which is just, incredibly rare.
This is not the kind of thing you want to do pro se. You will find the tenor of the courtroom much more different than when you went through the divorce - and if you are stressed now, imagine how much more stressed you are with an angry judge. Talk with an experienced family law attorney first - and depending on whether the court of continuing jurisdiction is Harris, Galveston, Fort Bend, or Montgomery county make sure you are talking with someone who spends the bulk of their time in that county, not spread across all four, since they spend more time with the local judges and have more time in front of them to know what works and what doesn't work.
Best of luck
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There is no law in Indiana that would allow you to increase support on the basis of abandonment. You would have to show a substantial and continuing change in circumstances that would warrant an increase in support. You can argue for a deviation in the support figure and I have in the past argued that a parents failure to be involved in a childs life places 100% of the burden of raising the child on the custodial parent and thus, should require an upwards deviation in support. Whether or not this happens is at the discretion of the trial court, but it is possible.
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