First and most important, what sort of music to you want to record? That can inform sensible options.
You might want to upgrade the interface, get something with 1/4" TRS line inputs instead of RCA jacks. Your keyboard will like that.
If your PC has USB ports you have lots of options. I would opt for something that runs USB-C and comes with a cable to use the older USB sockets, that will be viable longer. Firewire is still breathing but on it's way out. The new MOTU M2 looks nice, is very affordable and MOTU has a long history of supporting their interfaces and customers.
How much RAM is in your PC? Can more RAM be installed? RAM is good, more is better.
You may be able to find most things you want/need for free in this thread - http://forums.musicplayer.com/ubbth...e-quarantine-freebie-thread#Post3036360.
There are good free/affordable DAW options and I think there are some drum software options listed there as well.
A good pop filter should make your mic (and any future mic purchases) sound better, bonus because pop filters will never become obselete. Get a nice one, you'll only need to buy it once.
If the mic disappoints, consider getting a better one. Lots of options there, the Neat King Bee and Worker Bee are currently selling for much less than they are worth - not sure how long that will last. I have a King Bee, very good sounding mic. Big, heavy and ugly but it delvers the goods and comes with a good pop screen included.
Edited to add, I agree with Ronan on the SM 57 and on using the DAW your friends are using.
At the least you will want some nice headphones. A decent pair of monitor speakers is pretty essential. Too many options to list in those categories, would suggest keeping an eye on craigslist as sometimes some nice used stuff comes up at very affordable prices. One can outfit a studio on the cheap if one is choosy and moves quickly when opportunity arises. I know, I've done it.
Hopefully, others will chime in. Cheers, Kuru