Misfiring In 1 And 6 / Brown Dex-Cool

Hey all,
New to the group....Been driving the 1997 Catera with 64,000 miles quite hard lately, and the next thing I know, the CEL pops on and she starts shakin like crazy. Took her to the shop (not dealer) and they ran the codes saying that she is misfiring in cylinders 1 and 6. He suggested getting new spark plugs and wires all the way around. Does anyone have any idea how much this would cost, or if there is any chance I could do it myself. I've heard that Catera's have Coil On Plug (COP) ignition systems....would this make the task more difficult/what exactly is COP? Also, I refilled the slowly leaking coolant the other day, now the coolant looks a dark brown? P.S. Here are some links to pictures I took today....I'm not quite sure what it is im looking at although it appears to be a plug wire with spark plug that just pops in.... anyone know? If it is a spark plug, I take it that it isn't good for oil to be surrounding it?
Thanks all

http://www.uploadimages.net/images/897510almost_out.JPG

http://www.uploadimages.net/images/507221all_out.JPG

You probably blew a head gasket judging by the brown coolant. Check your oil level.

Coil on plug is exactly what it means. On "older" vehicles there was one coil, a distribuitor, and spark plug wires to transmit the spark to the plugs.