OK, you are on a calendar year, way easier than some fiscal years.
Why not use something like:
if now in CDate(year(now), 1, 1) to CDate(year(now), 3,31) then
...
else
if now in CDate(year(now), 4, 1) to CDate(year(now), 6,31) then
...
I don't know this for a filter or what, but this should work...when I tried the above formula, it just subtracted 3 months from the current date (probably, not what you wanted)
HTH