Sounds like you are on your way to a good barleywine. By "German Ale Yeast", it sounds like you are using the yeast cake from a batch of Wyeast 1007. That's a good clean yeast that will work well with a barleywine. It is slow to drop out of solution, but since this is a barleywine, you will need to let it sit for 6-8 months anyway. You are to be congratulated for avoiding the most common first barleywine mistake.......underpitching.
I do have a few more hints to make it go better. First aerate well! You need lots of O2 in there at the beginning. If you shake the crap out of the carboy until you think your arm is ready to fall off, you are only half way there. Rest up for 20 minutes or so and do it again. Your yeast will thank you.
Next, do the mash part at no higher than 150°. Actually anything in the range of 147° to 150° will work fine, so don't worry if the temp drops a bit. This will produce a more fermentable wort. More on that in a bit.
If you are planning to go higher than 1.090, consider using a pound or two of ordinary table sugar as part of your fermentables. Extract, depending on the brand, will have a relatively high percentage of unfermentable sugars. The low temp on the partial mash and the table sugar will compensate for the unfermentables. Without exception, every all extract barleywine I have tasted has had to high a final gravity and tasted way too sweet. An FG in the range of 1.024-1.029 is about right for a 1.090-1.095 OG barleywine.
Hope everything goes well for you.
Bugeater Brewing Company