bro city lues under 1.3 category because it has 1298cc engine while swift lies under 1.3-1.5 category because swift has 1328cc engine. That is why there is a difference in registration cost.
It is expected that the new city base model will be cheaper than the xli (approx 1600k expected as xli is 1628 oe near). Then wait for next model (6 months) in the mean time increase ur budget and then go for new city base model, but still nobody knows how new city will perform in Pakistan.
And nothing is perfect in this world, but always you have to go for a better option if its possible.
Rest the choice is yours.