Unfortunately, there is no adobe camera raw plugin that works in cs5 that will allow you to open your Canon Digital Rebel SL1 EOS 100D EOS Kiss X7 files directly in to photoshop cs5.
(camera raw 6.7 is the newest version that works in cs5 and you need at least camera raw 7.4)
Besides updating to a newer version of photoshop, you could use the 8.6 DNG Converter to convert the SL1 files to dng copies, which should then open in photoshop cs5.
Which version of windows are you using?
Adobe - Adobe Camera Raw and DNG Converter : For Windows : Adobe DNG Converter 8.6
If you have windows xp or vista, then use the 8.3 DNG Converter
Adobe - Adobe Camera Raw and DNG Converter : For Windows : Adobe DNG Converter 8.3
how to use the dng converter