Database upgradation from old database to new installed TL

[kalavathi]

Hi,
I installed my testlink in ec-2 instance and configured the rds database .Unfortunately I lossed my testlink folder in /var/www/.So I started newly installtion and after going to the page of database configuration ,I configured the old database credentials but I am not able to retrive the old database to newly installed testlink.It coming to the freshly installtion page.
Can you please suggest me how to get out from this??
My old database contains hundreds of testcases.

Thanks in advance
Regards,
Kalavathi jeeru