Yeast dilema

I'm brewing my first AG beer today, american cream ale, things are going okay considering this is my test run of my equipment, only had to make a few changes. My problem is I ordered my grains and yeast 3 months ago, I thought i was getting dry yeast but ended up getting wyeast british ale 2 liquid yeast and has been stored at room temp for the last 3 months. I would assume this yeast has gone bad. I don't have access to any yeast other than mail order, 2-3 days. I also have a dry yeast pouch from a extract beer kit, canadian lite beer. An other option is to use a previously brewed extract beer that I brewed 3 months ago. Which yeast should I use?

You can make a starter with the liquid to proof it...... Dry yeast should also be refrigerated... as for the 3rd option, are you refereing to a yeast cake that has been in the fermenter for 3 months? That seems a bit old to me....

No, just some beer that I have bottled

your best bet is probably to pitch the dry yeast unless you can make a starter to proof the liquid yeast.

Since my wort is already boiling, I probably don't have time to do a starter, how long could I leave the beer before pitching the yeast.

I don't know what you did. I think it is too late to activate the liquid yeast, it can take from several hours to a week to swell up depending on the health of the yeast, and from what you have said, I suspect it's in bad shape.

You should use the dry yeast to save the beer.

Save the liquid yeast for your next beer. Activate it a week (or more) before you want to use it. I expect it is still good, but the cell count will be down, which will result in a very slow activation. You should also be prepared to make up a starter when the pack has swelled.

ALWAYS keep a spare pack of a 'good' dry yeast on hand in case of an emergency like this. I keep a couple of packs of Nottingham just for this reason. It's cheap, clean, can ferment at low temps if necessary, and is a high attenuating yeast in case of a stuck fermentation.

Thanks, sounds like a good plan