First off, any of those claims of 5 or 7 mile ranges are only true under ideal conditions...ie, no obstructions like hills, trees, houses, etc....
Two, the above post is correct. FRS radios are limited to .5 watt of power by the FCC. Because of that they can only have an ideal range of about 2 miles. Chances are that if you find a radio that advertises more than that then it is a GMRS radio. GMRS radios do require and FCC license to legally use....even the dinky 1 or 2 watt bubble pack models you find at Walmart. The license can be obtained at
www.fcc.gov but it will cost you $75 the last time I looked. It lasts for 5 years and covers everyone in your immediate family.
If you are looking for a recommendation on a good GMRS radio that will get you at least 4 or 5 miles...realistically...then I suggest you look at least a 3 watt output model with a detachable BNC or other style antenna. RadioShack and Midland both offer models along this line at some reasonable prices.
You can also check out
www.bills2way.com and
www.popularwireless.com for more radios and a great messageboard about these type of issues.
Hope this helps.