Putter fitting and club head speed.

On monday i took the opportunity to have a putter fitting that my local club were offering. Since i have started playing again after a lengthy lay off i have noticed my putting has been awful so any help was welcome. The fitting took some 20 minutes and they explained the putter ive had for some 17 years was not for me anymore. Armed with the info they gave me i tried several putters but one stood out as soon as i held it. just mucking around with it the last few evenings has really given me confidence but the weekend will show if it gives me the boost i need when playing my first round with it(Anyone looking for an odyssey dual rossie 2 that i may well have for sale now lol). Also while there i had a swing speed check with my 7 iron which showed an average speed of 78mph. Does anyone know if its possible to tell what my driver swing speed would be from my iron swing? Thanks Mike