Understanding TPA

I have been lead to believe that within minutes or hrs after someone is given TPA, there should be instant improvement in their condition/symptoms. Is this accurate?

Here is what the National Stroke Association's website had to say:

"a five-year trial, conducted by the National Institute of Neurological Disorders and Stroke (NINDS) found that carefully selected stroke patients who received Activase within three hours of the beginning of stroke symptoms were at least 33 percent more likely than patients given a placebo to recover from their stroke with little or no disability after three months."

Three months? So what does that mean? That the success of the drug can be seen in minutes or hrs after the stroke BUT also 3 months later??

I read another news article where they say:

"The articles always seem to include an anecdote where some one gets tpA and jumps off the table instantly cured. This is not supported by the literature where the gains are actually small functional improvements down the road.

Can someone relay to me their knowledge and experience about TPA?