Neither party in a 2 party system can ever bring about true reform. They must always appeal to at least 51% of the nation. Such marketing requirements limit any radical departure from the status quo.I actually understand what you're saying. The wins, as impressive and exciting as they are will not turn the Republican party into a reform party. Instead, they will steer the party further right.
2012 will be the key year as there are many Democrat Senators up for re-election. There also will be a TeaParty candidate on the Republican ticket I'm sure. Probably the honorable Jim Demint.
Time will tell. By 2013, the Republican party will either be the same GOP having co-opted the TeaParty candidates or they will be a TeaParty lead reformed GOP. It really comes down to can the TeaParty sustain the momentum that has built over the past year.
This is why the Tea Party cannot work within the Republican Party. But even if they run as a 3rd party, they'll have to address the issues listed before. They can't pretend that other issues don't exist.