To convert 25i to 29.97i in AviSynth, try this.
Mpeg2Source()
Bob()# Change this to your favorite deinterlacer.
Spline36Resize(720,480)# or whatever
ChangeFPS(60000,1001)
AssumeTFF()
SeparateFields()
SelectEvery(4,0,3)
Weave()
You might not like the result; I don’t much. And I don’t envy you your source material.