I second the gymrats community recommendation. and for the love of sugar, dont make a post there if you start off saying things like "I thought small weight/more reps was the recommended thing for toning vs. bulking up." - that is 100% false. and you'll get reamed for mentioning it. (they are snarky over there, but ridiculously helpful w/a wealth of fitness knowledge)

but seriously, check out the community info, read stumptuous (linked in the info) - and learn that lifting heavy things is really, really good for you. and vicar is right: just up the incline on your treadmill, and dont use weights on the treadmill. mebbe do 10mins at a really high incline doing a brisk walk, then get off and lift some heavy stuff a few times, and call it a day. you'll be amazed what a difference it'll make. but prepare yourself w/some knowledge first. :)

sorry, dont mean to come off preachy or anything - just, being in that gymrats community - you see ppl come in ALL THE TIME w/this notion that tiny weights + lots of reps = worthwhile. and that philosophy couldnt be further from the truth... it's just become a knee-jerk reaction at this point to help point misled aspiring fitness folks in the right direction. :)