Here is a great resource for dofollow blogs. www.inlineseo.com/dofollowdiver/ I also use and recommend commentkahuna.
if you've automated your comments, I wouldn't worry about whether or not its nofollow. It's all good. If ypou're doing it by hand, consider automating it.
I just grabbed this list from another thread, so I have no clue about the quality of the blogs (or their DoFollow-ness). Try a quick search for stuff like this, there are tons of lists already on DP ------- Here you go! THE LIST PR6 http://www.figby.com/ http://www.midasoracle.org/ PR5 http://www.jemjabella.co.uk/ http://heiseidemocracy.com/ http://www.shandyking.com/ http://www.dotsauce.com/ http://engineering.curiouscatblog.net/ http://www.asgeirhoem.no/ http://middlezonemusings.com/ http://andybeard.eu/ http://lifecruiser.com/ http://www.lifeinthefastlane.ca/ PR4 http://www.wordpressmax.com/ http://jmorris.name/ http://redstaplerchronicles.com/ http://www.whatthefak.com/ http://www.totaldiatribe.com/ http://www.earnestparenting.com/ http://soul.beyondeternal.com/ http://www.roadlesstravelled.com.au/ http://smartwealthyrich.com/ PR3 http://freeadblogger.blogspot.com/ http://www.thedigeratilife.com/blog/ http://cooladzine.blogspot.com/ http://adryblog.net/ http://trcoach.com/ http://www.countrykitchenpantry.com/ http://www.melissamanske.com/ http://www.kilheeny.com/ http://thoushallblog.com/ http://www.reducingme.com/ http://www.timgary.com/ http://qualitynetdesign.com/ http://chenpn.com/ http://www.brilliantcheers.co.uk/ http://pajamaprofessional.com/ http://chrishoyt.com/ http://dereksemmler.com/ http://www.zr5.net/ http://armymomnj.name/ http://www.jonespc.com/ http://dorischua.com/ http://www.mycreditgroup.com/membersblog/ http://www.patricksays.net/ http://paulamooney.blogspot.com/ http://afrogtokiss.net/ http://veganmomma.com/blog/ http://www.simplekindoflife.com/ PR2 http://www.rottenbananas.com/ http://www.scribbleonthewall.com/
And if the tips you have already received isn't enough try typing "dofollow list" or "list of do-follow blogs" or "dofollow comment list" etc. That should give a list of enough blogs to comment on for the rest of the year. (Or you could focus on generating some quality backlinks instead..)