Get Revit Title Cell Data

Use this link and combine it with the changes for the SectionType below and I think this may get you what you want:

TableData td = vs.GetTableData(); // get viewschedule table data
TableSectionData tsd = td.GetSectionData(SectionType.Header); // get header section data
string text = tsd.GetCellText(0, 0);
tsd.SetCellText(0, 0, "my new title");