I created another SG and attached to the same VPC, but that won't work. The only alternative I see for now is to attach another network interface with a pubIP and add the second SG there. Is any way of increasing the limit of first SG rules limit in the primary network interface of the instance.
Okay found the solution. After you create a security group, and you attach it to the same VPC where the network interface for the instance is, and the same region, etc. Then, you go to network interfaces, right click, or select and click the action button, you click the Change Security Group, but this is tricky, you will think that you can only change from one to another group, but if you press CTRL and hold, you can select two or three groups and then click save, that will attach those security groups to the same interface.