Wow you have a lot of options including relocating! Just make sure you don't move for "the one" school as schools and children's needs change.
Also a word of warning regarding siblings. Most have IQ's close together but not all. My younger tests 15 points below the older. If my older scored around 140 that would put my younger below the cut off for most programmes. My younger had earlier milestones and was more verbal so i was surprised. Your younger is probably around 140 but if she is 155 or 125 solutions put in place for your older may not work for her.
