Hi,
Your first stop would probably be an LC. You can ask your CHN or at the hospital to see if they can recommend someone, or else find a private one here or here. You can ask when you call around what experience they have with tongue tie - they may even be able to suggest a course of action over the phone. Generally, it's either a pead dentist or a paediatrician who will release the ties. You may or may not need a referral, but they can let you know.
What's her nappy output like? Do you think it's possible you have an oversupply? What you describe sounds like it could be due to that, but would need more info to nut it out. An LC could help determine this, also.
Good luck.