Need some legal advice on a debt-to-court matter, please. I live in PA, and would like to do this myself until it reaches trial. Apothaker & Associates (AA) -- on behalf of AMEX -- mailed me their plans to seek an arbitration date from the court on a civil suit (debt collection.) Their ask is for me to notify them if I wish to conduct additional discovery. (The letter came only to me -- it didn't enter as a court docket.)

I need to know if I should proactively file "Request For Admissions, Interrogatories And Production Of Documents", or if I should let AA file their next motion and wait for a judge to grant a court date. (I really would like to get the case dismissed since I am representing myself and not ready for trial or pre-trial meetings.)

I think I need to file for discovery -- but I don't want to slip up on timing or a sequence technicality. I won't use a lawyer until it reaches pre-trial or trial. What became a dire need to delay AA's poor timing due to a poor job/funds situation has now turned into something that's growing -- possibly out of control -- but hopefully into something I can win (or settle cheap on.)

Sequence Background:
10/2010: Docket: Received summons of civil suit for alleged AMEX debt ($13k). Insufficient details listed in suit.
11/2010: Docket: I filed motion to dismiss
11/2010: Docket: judge ruled for AA to show cause
12/2010: Docket: AA answered
01/2011: Docket: judge overruled motion to dismiss, granted me leave to answer
02/2011: Docket: I answered, including affirmative defenses. (*details below.)
02/2011: Docket: AA filed a reply to new matter
06/2011: (outside of court): AA mailed me requesting my plans for additional discovery
07/2011: if AA holds true to word, they will ask the court tomorrow for arbitration.

Do I file discovery immediately? Or do I let AA perform their next action?

*Answer Summary:
1-2 Admitted that I was myself at my address
3-7 Lack sufficient information

*Affirmative Defenses:
Plaintiff failed to state a claim upon which relief can be granted. Plaintiff's Complaint and each cause of action therein fails to state facts sufficient to constitute a cause of action against the Defendant for which relief can be granted.
Plaintiff's Complaint violates the statute of Frauds as the purported contract or agreement falls within a class of contracts or agreements required to be in writing. The purported contract or agreement alleged in the Complaint is not in writing and signed by the Defendant or by some other person authorized by the Defendant and who was to answer for the alleged debt, default or miscarriage of another person.
Plaintiff's Complaint fails to allege a valid assignment and there are no averments as to the nature of the purported assignment or evidence of valuable consideration.
Plaintiff's complaint fails to allege whether the purported assignment was partial or complete and there is no evidence that the purported assignment was bona fide.
Defendant alleges that Plaintiff or the person or entity that assigned the alleged claim to the Plaintiff is not entitled to reimbursement of attorneys' fees because the alleged contract did not include such a provision, and there is no law that otherwise allows them.
Plaintiff's alleged damages are limited to real or actual damages only.
Defendant reserves the right to amend and/or add additional Answers, Defenses and/or Counterclaims at a later date.

Any good advice is appreciated. Thanks!