First of all, I'd recommend re-installing Sonar 8.5 Producer. That way you'll get all your VST instruments back for use in Cakewalk by Bandlab.
As far as free ones, there's loads about.
I personally like these:
http://www.dskmusic.com/ Elektrostudio used to do a fantastic range of free analog emulations, but the website seems to have gone. You can get them at
http://www.vst4free.com/index.php?dev=Elektrostudio - actually
http://www.vst4free.com is a great resource for loads of free VSTs.
One of my favourite free VSTi's is Cobalt by Leslie Sanford. It's a bit like a Korg DW8000 / Kawai K3 crossover:
http://www.lesliesanford.com/vst/plugins/ GTG synths are also not bad:
http://www.gtgsynths.com/plugins.htm You can get a free Yamaha XG synth here:
http://veg.by/en/projects/syxg50/ Note that most of these are 32 bit. I've personally not had issues with this, but some of them might not play well with Cakewalk's BitBridge. Investing in JBridge is a good option.