Hi Rahul,
Next to the option of a Generic DataSource using an InfoSet Query I see the following alternatives.
Alternative 1.
You can create a new InfoProvider (i.e. a DSO or an InfoCube) for the required dataset. You then create a Transformation from the InfoSet to the new InfoProvider. Now you are able to generate an Export DataSource.
Alternative 2.
You create a Generic DataSource using a custom Function Module. Here you have to develop similar logic as in the InfoSet (e.g. joins).
Altenative 3.
You can use APD (Analysis Process Designer) to write a dataset in an InfoProvider using a BEx Query on the InfoSet. Be aware that this is not a scalable solution (i.e. no packaging of data).
Delta can be tricky. Basically a Generic DataSource can be made delta-enabled (e.g. using a time stamp). However, I cannot judge how easy or difficult it is since I don't know the data context.
Best regards,
Sander