Hi Manoj,
Here is some info that relates to your two questions;
Q. How many clients can associate to the AP?
A. The AP has the physical capacity to handle 2048 MAC addresses. However, because the AP is a shared medium and acts as a wireless hub, the performance of each user decreases as the number of users increases on an individual AP. Ideally, not more than 24 clients should associate with the AP because the throughput of the AP is reduced with each client that associates to the AP.
From this Q&A doc;
http://www.cisco.com/en/US/products/hw/wireless/ps430/products_qanda_item09186a008009483e.shtml
As far as coverage goes, these are really just guesses without an in-depth site survey. But this document has some really good baseline coverage and distance ideas;
Clip"
As a matter of physics, there is an inverse relationship between wavelength and range. All other things being held equal, a signal transmitted in a lower portion of the frequency spectrum will carry further than a signal transmitted in a higher band. Additionally, a longer waveform (from lower in the spectrum) will tend to propagate better through solids (like walls and trees) than a shorter waveform. Because 802.11g operates in the same 2.4 GHz portion of the radio frequency spectrum as does 802.11b, it will share its fundamental advantage over the 5 GHz-based 802.11a. With 802.11b and 802.11g all things are not, however, held equal. Another fundamental rule is that as data rates increase, range decreases. 802.11b uses DSSS to support data rates of 11, 5.5, 2, and 1 Mbps each, with correspondingly longer ranges as the data rates decrease. 802.11g uses OFDM to support data rates of 54, 48, 36, 24, 18, 12, 9, and 6 Mbps each, with correspondingly longer ranges as the data rates decrease. The higher data rates supported by 802.11g result in shorter range than the range supported by the maximum 802.11b data rate.
From this excellent doc;
Capacity Coverage & Deployment Considerations for IEEE 802.11g
http://www.cisco.com/en/US/products/hw/wireless/ps430/products_white_paper09186a00801d61a3.shtml
Hope this helps!
Rob
