There is a metro station named “Akropoli” . From there you have to find the way to the lift that takes you up to the Parthenon. You can have a look from the path in this video, where a manual wheelchair user tried to get to the Parthenon, without success though. You should keep in mind that you should either contact them in advance to use the lift, or visit in the morning. Either way however, you may not be able to use, as it may be out of order.
I hope you make it somehow ^_^ But even if you dodn’t, the stroll around the Acropolis hill is a pleasant one, and you can take a good view also if you visit the new Acropolis Museum, which is totally accessible.