There was a thread a while back about rare beetles spotted in pakistan (including karachi), do a search and try to find it.
If you were in islamabad or pindi there would only be 2 names you'd need to know,... Khalid (mchanic) & Moqeem (parts supplier).
Not too sure who the guys are in KHI.
For a first car i'd suggest you get a 1200 or a 1300 standard car sice they are cheaper and have less rare parts. If and when you decide you LOVE beetles then you should "upgrade" to a deluxe, and after that you can either AGAIN "upgrade" to either a Vintage (oval/split window) or find yourself a good 1302 or 1303.
Good luck and remember as long as the car & engine are built properly from the start , you'll NEVER have problems.