what if too many RSS feeds ?

I have been using core aggregator module with more than 100 feeds and it was ok besides small matters.

But as Google sees links and not content in this case, I wanted my news to be nodes and that's why I begun to use FeedAPI.

But I have a problem:
Percentage of maximal PHP execution time (currently 240 seconds). At current settings, the FeedAPI cron process can run for up to 180 seconds.

Because of 180 sec. restriction I can get news from only about 30 feeds. the other feeds are not updated during cron.

1.question is this "240 secs. PHP execution time" a limit of shared hosting or PHP ? so if I move to a VPS, can it be solved ?

2.question, what can I do to solve the matter ?

thank you.