Don't know if you'll see this before the meeting ... but YES, definitely you can ask for breastfeeding assistance at a LLL meeting.
Different meetings handle things differently, but most Leaders will try to ensure that any new moms get some time to ask questions or share any concerns. We all remember what those early weeks can be like!
If you want a Leader to spend time observing you and your baby breastfeeding, then you might need to wait until after the meeting is over, or perhaps set up a time when she can come visit you. But at any rate -- just ask for what you need! They are there to help.
Good luck -- let us know how you are doing!