For illustration's sake, I priced out the below itinerary (not ideal as you have a LGW/LHR transfer, but you get the idea):

Flights and Price
Outbound - Tuesday 21 August 2007 12:40 21 Aug14:00
21 Aug Dublin Gatwick (London) BA8083
British Airways Club Europe
18:05 21 Aug 20:40 21 Aug
Heathrow (London) John F Kennedy (New York) BA0179
British Airways Club World 25000BA Miles & £ 692.80

Inbound - Tuesday 28 August 2007 22:30 28 Aug 10:20
29 Aug John F Kennedy (New York) Heathrow (London) BA0182
British Airways Club World 17:00 29 Aug
18:20 29 Aug Gatwick (London) Dublin BA8086
British Airways Club Europe

Price breakdown
Passenger Price BA Miles Taxes, fees, charges and surcharges* per person
1Adult £ 542.00 25000 £ 150.80 £ 692.80

On this WT+ MFU itinerary you would earn 190 tier points, and just under 10,000 BA Miles. You need 400 points for eurosilver

If status was important another £400 should see you safely into ticketed Club World on a Summer Offer and 240 tier points (320 if exEUR), just one Club Europe return shy of eurosilver qualification.

If you are just looking for a cheap flight then try flyzoom from LGW or flyglobespan from Liverpool.