I will acknowledge that it is sad that in the 5th largest city in US, I have to go to the suburbs to find a good tailor. I guess I'll go to Centofanti.
Well, still in Philadelphia is Ernesto's on 5th Street, just a bit south of South street. There are a few others along south 5th street as well, but I don't have any personal experience with them. http://www.ernestotailoring.com/
Again, not sure if they would do alterations, but it's worth a phone call. They do talk about making suggestions for your wardrobe, but given their primary business is making tailored clothing, that's no surprise.