While you can't contribute to an existing Income account once it's opened, you can close your current Income account and restart a new Income account with additional funds1.
Simply complete the Restart an Income account with more money form.
You may also be able to continue to contribute to super through an Accumulation account, depending on your circumstances.
1. You should be aware that closing your Income account and starting another one may have implications for your Australian Government income support, and tax, so we would recommend that you seek financial advice before doing this.