Rodeo Alarm Buzzer

I own a 96 Isuzu rodeo, V6. I've noticed recently, actually for the past 6 months that the tone of my car alarm/keyless entry becomes really weak. Sometimes when I lock it with the keychain, it doesn't even make a sound the but it does lock. I found where the buzzer is located and I want to get it replaced.

I'll do it myself but I don't know where to look or find these buzzer. Has anyone had to deal with this. I know the agency is charging $111.31 for it and I think I can find it waaaaaaaay cheaper than that. I mean it's just a buzzer. They gave me a part number of 8971355620. Not sure where I can look that up. I googled it but nothing. Imight need dashes with I don't know where they go.

Help anyone?