Welcome to the garage.
Service manual you can find via google, there are free manuals to download.
The cabin air filter i think you can find at www.justforjeeps.com
This a vendor here at jeepgarage and will give discount to jeepgarage members, check out their thread.
JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
KYB Gas-a-Just shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.