The Red Sox Web site has a lot of good tickets available for all 4 Angels games this week, no doubt due in part to the Sox rough start. Up to 8 seats together are available for most of the games in prices ranging from $28 to $95 per ticket.
There are also tickets available on the Web site for the Friday and Sunday night Yankee games, but those are single scattered tickets. Your best bet for the Yankee games might be to call the ticket office at 877-733-7699 from 10 a.m. to 5 p.m., Monday through Friday. By speaking to someone in the office you can probably get 2 or more scattered seats fairly close together, which you can't do on the Web site. Also, if you wait until Thursday, pairs of seats together are likely to open up for the Yankee games.
Calling the ticket office to buy them is also a good idea if you are buying a lot of tickets for the Angels series, as you will save the $4.25 per ticket online purchase service charge. (When you buy on the phone you pay a $10 service charge, regardless of how many tickets you buy.) The downside is that with the higher than usual availability of tickets, you may be on hold for a long time this week. Try calling right at 10 a.m.