Congrats on your purchase.
If the engine is completely overhauled then switch to any of these oil's.
SGO PREMIUM 10W-40 API-SG.
Havoline 10W-40 API-SL.
ZIC X7000 10W-40 API-SL.
ZIC X3 15W-40 API-SJ.
If you plan to use your car on Petrol only then get all the CNG components removed and get it tuned for Petrol only.
Get the Radiator serviced install Thermostat valve and make the Radiator fan auto and pour in some quality coolant.
Rest for buying new part's i only trust 2 shop's in Faisalabad for Suzuki part's
Lahori Suzuki, Mian Trust market and other one is Mehran Suzuki centre (Mehran Suzuki is better than Lahori though).
For good quality belts buy them from Chiltan Trader's 237-A, Shoaib Bilal Market, Near General Bus Stand.
Can't recommend you any perfect mechanic though.
For tuneup you can try Munazco Automobiles Near Main Bazar Jhumra road, Mansoor Abad...
For suspension work's there is a workshop in a street next to Municipal College Jaranwala Road. You can ask Shehzad Auto's there for them mechanic's name's are Arshad and Dastagir.