She defended her Flyweight title with success against Delia Gonzalez, Yvonne Caples, Johanna Peña-Álvarez[3] and numerous others, once only with a draw against Elena Reid.

On 9 September 2006, Halmich won her 53rd pro fight, defeating Ria Ramnarine of Trinidad and Tobago by TKO in the sixth round.

Halmich faced Reka Krempf of Hungary on 13 January 2007 at the Brandberg Arena in Halle (Saale), defeating her by a unanimous decision for the 44th successful title defense.

Halmich announced her retirement after her farewell fight on 30 November 2007, in which she beat Hagar Finer of Israel by majority decision (96–94, 97–94, 95–95).

In addition to her boxing career, Halmich has branched out into the world of business, as she became one of the first women boxers to have her own line of cosmetics.