Hear to Velukkudi Krishnan's (a google search will reveal the links) discourse on acharya paramparai. He describes in length the Sri sampradayam beginning with the Lakshmi, follwed by the alwars , ramanuja to present.
The book published on Sr ramanuja by the Nrsimhapriya trust too describes vaishnavism prior to ramanuja.
Dasan
G