I recommend getting the newest version of Pro Tools(what you have is not likely to work with any current OS anyway). Then, you can look at a huge assortment of interfaces(PT M-Powered ONLY works with M-Audio interfaces). To narrow down the options, you need to decide on what IO you need(inputs, outputs, # of mic preamps), what connections you have available(firewire, thunderbolt, USB3, USB3, etc), and how much you can afford to spend. This is also a good time to review your current computer and decide if it can keep going, or if it needs to be retired. Your old sessions SHOULD open on any newer version of Pro Tools, but some plugins may be changed or currently no longer available(if your current recording drive is old enough, it might use an IDE connection that has gone the way of the dodo bird, so copy them over to a modern USB3 external drive(in case you can't make a newer computer talk to the old drive).
If all this seems like too much work or too much money, go shopping for a used M-Audio FastTrack Ultra(or if you have a firewire connection, the Profire 2626 was the best M-Audio interface they ever made)
