Residential & Commercial Security - Locks, Keys & Dead Bolts - help replacing cheap handleset

I am trying to spruce up my house before putting it on the market. I decided to replace the handleset on the front door (first impressions count). I am trying to NOT drill additional holes in the door, but I can't find a set where the bottom screw will line up with the existing hole. My old set does not have any kind of identifier to tell me a brand name (I am thinking a no-name builders grade set).
Is there a "measurement" that is standard? Or a term for the measurement from the center of the lock to the screw on the bottom (on mine it is almost 8 1/2 inches).
Any advice would be appreciated!
THanks
Jennifer

Baldwin products make some great quality entrance sets, that are guaranteed for life.

Have a look at the range Products - BaldwinHardware.com (http://www.baldwinhardware.com/product_results.aspx?cid=1&csid=1&nav=1_6)

there are product templates that show measurements. Many measurements vary according to style and function

The Schlage Parthenon sectional entrance set has an 8.5" distance between the center of the main bore and the bottom screw.

See Schlage - Products (http://consumer.schlage.com/products/Productdetail.asp?StyleID=31)

Here is the template to support the product with the measurements http://consumer.schlage.com/products/pdfs/F300-Series%20Template.pdf

There are multiple brands that will probably be available but if price is a motivator, you might consider the Schlage option as a better fit. (cheaper too)

Baldwin are considerably better quality but are significantly more expensive (as they should be with their lifetime guarantee)