In Rose v. Thorpe, 240 Ga. App. 834 (525 S.E.2d 381) (1999) Thorpe, with the assistance of the Department of Human Resources (DHR), obtained a consent order requiring her child's father, Rose, to pay monthly child support. Five years later, Thorpe filed an action in which she obtained a retroactive modification of child support on grounds that Rose had fraudulently underrepresented his income in the earlier proceeding. This court reversed, holding that the proper way to recoup support by an obligor due to an under-reporting of income is by motion to set aside the judgment. But see Young v. Young, 188 Ga. 29, 31 (1) (2 S.E.2d 622) (1939) (holding that fraud which will permit the setting aside of a judgment is limited to matters which are extrinsic and collateral to the issue tried in the case and do not include fraud in procuring a judgment by false testimony). A motion to set aside a judgment for fraud must be brought within three years of its entry. O.C.G.A. 9-11-60 (d) (2), (f).