。
Even the bedding got dirty from the dust.
Literal
Bedding [also-も] dust [with-で] soiled-[unfortunately-てしまいました].
The particle も ('also, even') implies that other things got dirty as well — 'even the bedding on top of everything else.' 土埃 ('dust, dirt-dust') is specifically airborne or stirred-up dirt, distinct from ほこり ('lint, indoor dust'). ~てしまう marks the action as regrettable/unintentional — 'unfortunately got dirty.' で marks the cause.