Need Replacement Radio For 1999 Sienna Options

[acrumbacker]

Hello,
First post. I have a 1999 Sienna and according to my mechanic, the battery was draining through the radio. Pulled the radio fuse and the drain stopped. Several days later, battery still good and charged. I went to the local Walmart and purchased a unit but before installing, got online and noticed wires dont match up. Does anyone have a recommendation for a wiring kit that will match up to the receiver and existing wiring? The receiver is in the box so it can go back if there is a cheap replacement that will drop in using existing connectors.
My original receiver is an AD1702 with no CD unit. Is this an amplified unit? My first thought is no but want to make sure.

Any help appreciated