The 2.2 is just the PCI specification revision. 2.2 is essentially the same as 2.1 but has some changes like 66MHz bus speeds being allowed (though the mainboard has to actually implement it to use it). 2.3 is also minor changes. The current spec is 3.0 and is the last spec there will be now that PCI-Express is out. The card should work in pretty much any PCI slot as long as the notches match (which defines what voltage the card uses). Most boards in the last few years are at least 2.2 version. 64-bit PCI slots are also around, which is why the 32 bit is specified for this card.
You could save a lot of money and get performance that's so close you can only see it with a benchmark, by getting any cheap NIC these days. Does your mainboard not have onboard networking?