Well it's a WorldnetDaily link so we can count on the presentation to be biased, but even so It doesn't support the claim that a lot of women are serving "hard time" - no sentence is mentioned on most of the reports, even for worse cases than the one in the OP.
Some examples of where the sentence is reported:
A woman convicted of having sex with 3 students was sentenced to a suspended nine-year sentence and possibly faces 1 year in jail - although it may be simply a year under house arrest.
One teacher was sentenced to 1 year for a sexual relationship with a 14 year old
There's a 1-year suspended sentence for a relationship with a 16 year old.
These are all reasonably in line with the sentence in the OP. The last is a lighter sentence in a less serious case, the other two cases are more serious and recieved harsher, but still not heavy, sentences.
In short this link indicates that the sentence in the case given in the OP is reasonable. It might be considered light, if it were granted that homosexual cases deserved harsher punishment - but even then it is not necessarily unreasonable in the light of the info in the link.l