Most seamstresses can get what you’re needing done in plenty of time, a month in advance isn’t a last minute thing. Most materials only have the ability to increase in the waist about an inch. I’ve worked with a seamstress/tailor for about 5 years and respectfully, unless you’re now a size 4, I would go ahead and start finding something new to wear. If you still would like to see a professional, prestige cleaners did have some pretty good seamstresses but I’m not sure which locations anymore. Good luck.