Holy Cow, I'm glad I don't live in Georgia. Unless your local school district has a rule that applies, the State Ed Code does not specify ANY time lines for notices related to IEP's that are not contained within the actual IDEA regulations. That means - NO requirement for notices for the kind of IEP meeting you're describing. The SD is required to be able to prove that they tried to get you to participate. That's it.
The Ed Code language is totally focused on how IEP teams can go ahead and write/implement IEPs without parental involvement. Jeepers creepers.
You might want to look this up for yourself. Go to
http://www.doe.k12.ga.us/pea_board.aspx?PageReq=PEABoardRules
and download the PDF for 160-4-7.06 and 160-4-7.09
Tomorrow first thing I would shoot them back a certified letter saying when you want the meeting held (give them a range of dates or a list of specific dates and time frames to choose from that is at least 10 school days away). Tell them you want to receive copies of all reports, proposed baselines and goals, a proposed agenda and a list of people who will be in attendance 5 school days prior to the meeting date. And inform them that you plan to record the meeting - that should cover all the bases.
If you can you might want to take a copy of the letter to the school principal, school psychologist, your child's main Special Education teacher and anyone else you know would normally be at the IEP meeting and give them the copy. Tell them how sorry you are that the district didn't get in touch with you so that you could coordinate your schedule with the
other IEP team members (i.e. you're an important MEMBER of the team and should be treated that way). Since it's such short notice and you had to send your reply to the district the same way they communicate with you (i.e. by snail mail) you were sure they (the teacher, etc) would want to know right away about the need to re-schedule the meeting and the dates you are available. So you brought them a copy of your note.
At the minimum I would try to drop the note off to the classroom teacher and principal since it is such short notice.
Sweet as sugar to everyone. Say as little as possible about what will happen at the IEP meeting if you feel that's appropriate. You're just being professional and letting them know that the meeting needs to be re-scheduled. Do not offer excuses or reasons why you can't do the proposed date. You have "a previous engagement" is good enough if you feel that you must give a reason.
If someone gets pushy, you can push back a little but not much. Think of these people as co-workers - difficult folks perhaps but you don't really want to make them even harder to work with by getting them mad at you over little things. Silence is good for this. The intrusive "why can't you reschedule your appointment?" question can simply be met by a stare held long enough to make the other person uncomfortably aware they have committed a faux pas.
I would also call the Special Education program person for your school and let them know you are sending the letter about re-scheduling the meeting. Ask if they would like you to fax it to them if that is something that is easy for you to do. If so, be sure to print out a receipt from your fax machine showing the date/time/#pages sent so you have proof you faxed it. This is in addition to sending a certified letter.
Alternate in addition to mailing is to take a copy of the letter down to the district offices and ask them to date stamp the letter as received right there in front of you before delivering it to the Special Education office.
Remember the golden rule of IEP meetings: Always prepare and conduct the meeting as if you were going to due process. Dot the i's and cross the t's. The SD will - so must you.
Good luck