If the OEM charger is going to be suspect, you’re much better off with an aftermarket one that you know is going to work. The difference in wattage means it’ll charge less quickly than the OEM one. If you can live with it, it’s probably the best option. Since I fix computers for a living, I have a huge pile of universal chargers, whenever I have to set up a new machine, I don’t even take the OEM ones out of the box.
If the end of the charger is loose when it’s plugged in, make sure that the connector isn’t loose in the laptop itself.
As far as the express card goes, it won’t make the external speakers work. Are you looking to upgrade or are they just not working?
Cheers,
Matt