Move RDS instance from EC2-Classic to VPC

I am currently migrating my production system from EC2-Classic to VPC platform.

All is done except for RDS instance, which is still in EC2-Classic. My original plan was to do migration with some downtime: shutdown all instances, take database snapshot, create new instance in VPC from this snapshot (RDS "Restore snapshot" feature).

Unfortunately when I tried to do this I realized that I cannot restore to the type of instance I want. When I click "Restore" Amazon offers me only a limited number of options:

• Expensive db.m3, db.r3 instances
• Previous generation db.t1, db.m1, db.m2 instances

Ideally I'd like to create db.t2 instance, is it possible to do that somehow?

Also, is there a way to migrate with zero downtime? So far I've found nothing in Amazon docs.