Gregg's in Bellevue no longer does rentals (I think). The closest bike shop I can think of that does is the Montlake (possibly renamed Kirkland) bike shop in Kirkland which is a short bus ride away.
Check out the 230 bus route between Bellevue & Kirkland here:
http://transit.metrokc.gov/tops/bus/...s/s230_0_.html
Google maps can give you point to point transit schedules, walking directions, and bus arrival times (very cool) The fare should be $1.75 or $2.00, depending on the time of day.
Here's a link to an earlier thread about Bellevue Routes, but there are a ton more out there. Reply in that thread if you are interested in other routes:
http://www.bikeforums.net/showthread.php?t=535482