Villa are only one point above the Barclays Premier League's bottom three ahead of the home encounter with fellow strugglers Southampton.
A lengthy injury list has deprived Lambert of several experienced players and he is aware of the need to strengthen before the end of the month.
But Lambert, who spent £23million during the summer transfer window, also knows the club club "cannot go bursting into major debt."
He said: "I understand the finances of it. The club cannot go into major debt. It's got to watch itself.
"It's something I'll meet head-on. I don't know how much, off the top of my head, the chairman (Randy Lerner) has put into the club. I'm pretty sure it's not light.
"I've spoken to him. There are one or two lads there that we will try to get. A lot is dictated by finance. We need a bit of strength in the middle of the pitch.
"Prices in January can be so inflated that you can pay through the nose for someone, and it's a guy you maybe don't want at the club.
"We have to build this club and not let it go back to what has happened before."