、。
She went out of her way to buy me a really nice model airplane for Christmas.
Literal
She [topic-は] Christmas [on-に], really wonderful model-airplane [object-を] me [for-に] specially-went-out-of-way bought-for-me.
わざわざ is one of those Japanese adverbs that's hard to translate cleanly — it means 'going out of one's way, taking the trouble to do' something one didn't have to. It carries either gratitude (when noting someone's effort on your behalf, as here) or mild annoyance (when noting unnecessary fuss). Pairing it with 買ってくれた ('bought for me') makes the gratitude reading clear: she didn't have to, but she did, and the speaker is appreciative. 模型飛行機 ('model airplane') is a transparent compound: 模型 ('model, miniature') + 飛行機 ('airplane'). The 僕 marks this as a male speaker.