In reply to Iskassasya:
All C1,2 and 3 crampons should fit your B3 boots, so your old ones will fit too!
As a general purpose crampon I'd recommend Grivel G12's with a Newmatic (plastic toe bale and heel lever) binding or similar 12 pt models from Petzl such as the Vasak or Sarken and Black Diamond models such as the Sabretooth and Serac.
I'd stay well clear of more technical crampons with a wire toe-bale until you are climbing Grade 5 and above and even then you'll still get away with G12's!