Paired samples statistics (table 1): pretest score mean= 41.6667, post test score mean= 93.3333, N=3
Paired samples correlations (table 2) Correlations= -.277 , Sig.=.821
Paired samples Test (Table 3) t=-7.750, df=2, sig(2-tailed)=.016
The significance level in Table 2 is high while that in Table 3 is low. Should I
reject the null or reject the alternative hypothesis in this t-test?
That will depend on which null hypothesis you are testing. At a guess, since this is a t-test, you want to see if the mean changed, and that would be table 3 which is significant (that is, the means changed).
However, I'd be a little leery. There was a huge change not only in the mean scores but in the standard deviation – it was much lower in the post-test (see Table 1). Was this expected? Also, table 2 shows that the correlation between pre and post test is quite low — in fact, it is negative — which is odd. You would expect a positive correlation between two tests.
Finally N is only 3.