Creating a regression testing sprint in agile

Question

I am in a team which we are delivering a product right now. We are preparing for regression sprint it will be the next sprint. In this sprint testers will have to test the whole application to ensure that the application in a stable state.

The problem is in development team actually we finished the queue of tasks that is needed for the current release, and we have a large queue of tasks but in another release.

I can think of two options to solve this issue

1. Doing a regression with some of testing team and let the other testing team join the development team to work in the next release
2. Dedicate a sprint to regression & bug fixing.

Hint: we have limited resources in testing so we can't offer a team for testing the regression