Yeah, you are better off buying individual microhphones. Generally, the mic's in those drumkit packs are junk. Most drummers don't know any better and think " I can mic my whole kit with this cheap mic pack!" but there is a reason the mic pack is so cheap - it's junk.
Save your money and get a pair of Marshall MXL
603's for overheads - they seem to be the standard budget winner as far as overheads go - they chould cost you about $160 for the pair, or you could try the Marshall
990's, which sell for about $50 each - they have the same microphone elements as the 603's, inside a different microphone case.
Then, once you have the overheads, you could add a decent microphone specifically designed for the bassdrum, and build your mic collection from there. The reason I say this is - with those mic pack's, at some point you want have any use for those crappy mics - and you'll be out some money - if you start with at least decent mic's, you will get years of use out of them. I have a pair of PZM microphones that I purchased 20 years ago, and they still work just fine.
Tim