Question : Renew SSL certificate with 2048 bit key length

I am renewing an SSL certificate that is currently with one company though I am renewing the certificate with another company. Apparently our bit key length is 1024 and needs to be 2048 or 4096 for the SSL certificate with this new company. The tech could not tell me what I needed to do other than it was on my side. Can you please give me instructions for upgrading our 1024 bit key length to 2048?
Thanks

Answer : Renew SSL certificate with 2048 bit key length

Server is running windows 2003 R2 sp2