i think u should join some correspondence course check out if bansal provides it or not or u can join resonance dlp but besides all this keep on referring NCERT too.Nowadays jee is becoming NCERT frriendly.As far as ur B.Sc. is concerned i believe here u have to synchronise urself between ur present studies & ur jee preperation.
If the 1st button of a shirt is wrongly put,all the rest are surely crooked.So always be careful on your 1st step.Rest will come correct...