The Convention Center West Building is located on 2nd Street, south of Monroe (across from the Hyatt Regency. There are two garages that are easily accessible; both are $10 / day:

Option 1 (see #1 on parking map)
Convention Center West Building (underground) 2nd Street just south of Monroe.
Enter at the northeast corner of 2nd street.
After parking, follow the signs in the garage to the Convention Center entrance.

Option 2 (see #2 on parking map)
Regency garage on 2nd Street, just south of Adams.
Enter from 2nd street.
After parking, cross the street to the Convention Center West Building on the east side of 2nd street (next to Starbucks).