In order to break WEP you need to catch 2 packets with the same key and reused IVs. The number of packets in order to break the key depends on the length of the IV, but you usually need more than one thousand.
In your case probably your 3 packets do not share the same IVs. This means that you cannot break easily the key. Your only way will be brute forcing the key and for that, you do not need any live attack.
You can use airdecap-ng for bruteforce the key.