1. Download Client 2.4.3 tbc. (include some Addons)

2. You can download MultiBot Addon and put it in your World of Warcraft 3.3.5a/Interface/AddOns folder.

2. Also, you can download Mangosbot Addon too, and put it in your World of Warcraft 3.3.5.a/Interface/AddOns folder.

This is a list of addons that may be helpful to you:

Addons