A yellow filter is colour correction to counteract the blue tendency of EIR, red is more extreme. Have a search on www.flickr.com, I just tried "eir yellow filter" and "eir red filter" (without the quotes around all three terms) and found plenty of results. The ones in my IR set http://www.flickr.com/photos/nord_mo...7607606277497/ are shot with medium yellow.
I shot a roll in September with an expiry of 12/2006 and it looked to have just the same colour balance as the roll I shot a year previously which had just expired at the time. All of mine is stored in a freezer, and was bought from a dealer who presumably also stored it correctly. If yours hasn't been frozen, it's likely to have lost IR sensitivity to some extent.
I find setting the ISO at 250 on my Nikon FE gives good results on sunny summer or autumn days in the UK. As you only have one roll I would just go with that, otherwise I would suggest bracketing to give you a better idea for your local conditions.