18"x18.5" - The 18" stands for the diameter of the wheel (ie: how big the rims are), and the 18.5" must be a mistake to mean 8.5" which signifies that the rims are 8.5" wide (ie the thickness of the rims if looking from the back of the car will be 8.5" wide on each rim)
ET: 37 - This is referring to the offset of the wheels and is basically the distance from its hub mounting surface to the center of the wheel (kind of hard to get into so you can look it up here for more in depth info: http://www.tirerack.com/wheels/tech/...jsp?techid=101
PCD: 120 - PCD stands for the Pitch Circle Diameter and this measurement is the distance between the center of two diametrically opposite bolts...This can sometimes be referred to as a 5 X 120 figure meaning that there are 5 bolts with the distance of two diametrically opposite bolts being 120mm apart from each other.
C.B: 72.6 - CB stands for Center Bore and basically is the part (or hole) where your rim attaches to the car. The 72.6 is referring to the center bore of the hub being 72.6mm in diameter.
It may all seem a bit confusing but once you go through the act of buying one set of wheels you will learn quite a lot...as far as "will these rims fit on my car" there are a lot of things one can do to "make" a desired set of rims fit...anywhere from rolling fenders to adding spacers...your best bet is to call up a local shop and act as if your interested in purchasing rims from them but are unsure of the sizes that will work...get them to list off your specs and there you go!..good luck with the purchase