Atlanta Public Schools' purchase of a 56-acre site in northwest Atlanta for the city's new Buckhead-area high school should be completed by summer, with a goal to open the new school's doors by fall 2013.

Meanwhile, the city school board's public acknowledgment Monday night of the proposed $56.2 million deal, which involves the IBM complex on Northside Parkway, thrilled parent leaders. If nothing else, they said it means the system is taking a concrete step to address overcrowding in Buckhead-area schools.

But even as the congratulations continued Tuesday, the reality of a two-year-away move-in date means parents are also not about to let up on the pressure. They have pushed system officials for more than a year for a long-term plan for rising enrollment that has crowded their schools.

"We're not going to take our foot off the gas pedal," said Reide Onley, PTA co-president of Sutton Middle School -- currently Buckhead's only middle-school campus. "We've got to have a good plan in place."

The new high school is part of that. The system over the last several years has built and renovated most of the six elementary schools that feed into Sutton. It has also opened annexes to expand their capacity as elementary school enrollment swelled, which parents and staff credit to the area's stability in addition to curriculum changes that increased local schools' rigor.

This has caused, however, a bottleneck at Sutton. Its student population last school year spilled past planned capacity of 1,040 students. Its enrollment by fall reached 1,199 and is expected to rise further when the state next counts in March.

Atlanta officials, well aware of those projections, announced early last February their plans to build a new high school to replace the current North Atlanta High School, which sits just south of the new location on Northside Drive in Buckhead. Under current assumptions, which parents have backed, North Atlanta would become a second middle school -- housing seventh- and eighth-graders -- to relieve overcrowding at Sutton, which would then become a "sixth-grade academy."

What parents such as Onley are looking for now, however, is how the system will make that work. He said Superintendent Beverly Hall has said her staff would conduct a study but has not yet released it.

Nancy Meister, who represents Buckhead on the city school board, said in an e-mail to parents Tuesday morning that the size of the proposed site "will allow the district to stay ahead of the anticipated growth." She also said it "will allow for athletic facilities such as a football practice field, soccer field, softball field and baseball field. "

System officials are also optimistic. As opposed to undeveloped property, the IBM site already has power and sewer systems, infrastructure and buildings that could be renovated for school use and paved parking. Final construction estimates won't likely be available until at least summer. But officials have said previously the school could cost $35 million to $45 million to build, although that price did not include land.