Try to find the .debs in question over the internet and extract the files by hand.
omap3-dsp-baseimage-ti_0.i3.6-20+0m7_armel.deb omap3-dsp-hd-codecs_0.3.9-6+0m7_armel.deb omap3-dsp-libraries-ti_0.i3.6-20+0m7_armel.deb
omap3-dsp-baseimage-ti_0.i3.6-15+0m6_armel.deb omap3-dsp-hd-codecs_0.3.8-7+0m6_armel.deb omap3-dsp-libraries-ti_0.i3.6-15+0m6_armel.deb
On a side note - we should solve that repos issue somehow, maybe we should start pestering Microsoft, dunno.