Air carrier First Officer describes delays in receiving a revised flight plan over ACARS that results in crossing 50W prior to receiving weather; and sending the acceptance message.

Narrative

When I returned from break as the Relief Pilot we were about 1 hour prior to GRIBS and requested oceanic clearance. Half an hour prior to GRIBS; we still didn't have our clearance. We received a CPDLC message to get the clearance by voice. It was difficult to here the Controller and it took some time to get the clearance (about 10 minutes). The clearance involved a route change. We sent a message to the Dispatcher to update the computer fight plan which he did. The first flight plan was incorrect (incorrect airspeed) so the Dispatcher sent us a second. These flight plans are very long and it took about an hour to get the correct version. While the flight plans are uploading; it is not possible to uplink or downlink other info. We had not received ETOPS weather or sent an acceptance message. The Captain had looked at the previous weather so he was comfortable proceeding past the ETOPS Entry Point. By the time we received the correct flight plan; the ETOPS weather from the Dispatcher and sent the acceptance message we were about 60 miles past 50W.