Increasing the range of a cruise missile is much more complicated because of its compact size. On the other hand, an ICBM can be of more than two stages thus allowing it to carry huge amount of fuel. It's the re-entry and acquiring target that require advanced technology and Pakistan has already mastered the technology of acquiring target, now Pakistan needs to master the art of re-entry and with the help of her friends Pakistan can do it within 2-3 years.
Good,now we're upto something...
Babur was an example,anyway we didn't increase its range,we made a new one...
and FYI,it wasn't about the range...Babur had delays because we couldn't get any help on it,not even from the Chinese...
As for the ICBM,its not that simple.....a good ICBM should also have counter-measure suites (for evading the best ABMs),MIRVs,communication at hypersonic speeds,adequate launch platforms,a reliable guidance system (so far,Chinese satellites are helping us on this) and much more that we both don't know about...
An ICBM of 11,000km should be a masterpiece,as US will know about it much beforehand.....it should not be something as V-2 (just for an example)..
Also,it should be kept in mind that US is testing Airborne laser missile defence(600km range,can take out a missile in boost phase),which would be soon operational.....it could be fielded in Afghanistan...