[susan53]

You can never ask a question like this without specifying the context - because the choice of verb form always depends on it - in particular, the temporal reference point established by the context.

So :

1. If the reference point is "now" - ie the speaker means the two weeks immediately preceding the moment of speaking, then (1) is correct. The sentence describes past events which have a present result - and so the present perfect is used. Eg :
I'm sorry - but I can't offer you a slice of cake with your tea. I'm useless at making cakes. I've made four cakes over the past few weeks and they've all been horrible.

Present result (no cake in the house) of some previous past events (making the cakes)

2. If on the other hand the reference point is past (eg last April and the sentence refers to the two weeks before that, then (2) is correct. Eg :
I hate making cakes, but David kept asking me for them. He stopped last April though. I'd made four cakes over the previous two weeks and they'd all been horrible. He never asked again!
Past result (David stopped asking me to make cakes) of some previous past events (making the cakes).

So :
1. The present perfect (have+past participle) describes events happening "before now" with a result "now".

2. The past perfect (had + past participle) describes events happening before a specific time in the past, with a result at that time.