She bought some fabric. She's planning to make her own dress.
Literal
She [topic-は] fabric [object-を] bought-came. Own dress [object-を] make [intention-つもりだ].
買ってきた uses the ~てくる pattern: 'went and bought (and came back with).' 生地 (きじ) means 'fabric' or 'material.' The second sentence introduces her intention: ~つもりだ means 'intends to' or 'plans to.' 自分の (one's own) specifies she'll make it herself.