Got a few questions:
1) You mentioned that it will take a generation for your manpower to recover. So you are saying that its going to take roughly 25yrs before you are at full manpower?
2) Is there any way for you to help one of Rome's or Seleucid's generals/governors to create a bit of trouble or convince them too? If it is possible and you have a good chance of being successful w/o detection then I would do so. If you have a good likelihood of being caught then its not worth risking Roman or Seleucid ire.
3) Is there any way for your to diplomatically annex a nation? If there is then I would attempt to do so to the Greek city states. Its nice to get a little money but even nicer to get the whole package.
I would work on getting my economy humming. Build some buildings to help out with both the economy and give us a culture boost. Establish a few more trade routes. Colonize a bit more or speed up colonization if possible.
If the chance arises finish off Illyria. They could still cause some mischief if we are occupied elsewhere and they may be a tempting snack to Rome after they are done sticking it to Carthage.