If the one reading from the Torah (whether it be on Mondays, Thursday, Shabbos, etc) has to say the bracha of “Ha-Gommel” when should it be recited? Is it ok to say it after the last aliyah before he recites Kaddish. Or perhaps this is an interruption (“hefsek”) and should be said after the one reading from the Torah (“bal koreh”) says Kaddish?
Ha-Gomel can be recited before Kaddish. However, some are particular to recite it after Kaddish, and this is the preferable method.
The Kitzur Shulchan Aruch (69:5) writes that somebody who finished reciting Ashrei at Mincha and now wishes to put on a Tallis should say some extra pesukim before Kaddish, so as not to make a hefsek.
Sefer Nesivei Halachah (2:219, p. 96 and note 8) writes that this principle also applies to the berachah of Ha-Gomel, which should be recited after Kaddish and not before.
However, the ruling of the Kitzur Shulchan Aruch is not apparently universally accepted (see Mishnah Berurah 54:12).
In addition, there are a number of distinctions that can be drawn between the case of the Kitzur Shulchan Aruch and the case of Ha-Gomel: For Ha-Gomel the custom is to make the berachah at the time of the Torah reading, so it is less of a hefsek; also, the Shaliach Tzibbur is not making the berachah, but only the person who received the aliyah; furthermore, see Mishnah Berurah 292:4 (citing Magen Avraham) that a single pasuk is not a hefsek.
For more sources on this question please see here.