Pro-ject RM 5.1 predicament

Hello all,

Long story short, I bought a like-new Pro-ject Speedbox II and an RM 5.1 WITHOUT a tonearm or cartridge, sold together. My dad's old Fisher plays unbearably slow (my speculation is that the motor is dying since I replaced the belt fairly recently) so I'm hoping the Speedbox might solve this, although I'm not at all confident it will. The primary reason I bought them was that they were $200 for both and the Speedbox alone is normally $160.

My questions are fairly simple:
1. Would another tonearm work well with the RM 5.1? If so, would any of them relatively inexpensive (sub $200)? I'm not sure I want to buy a Pro-ject tonearm since they're so expensive and I'm trying not to spend very much money right now--I'm really just looking for something temporary that will be better than my Fisher MT-6117 (shouldn't be very hard since it's platter is imbalanced as well).

2. If getting an inexpensive tonearm to work with the RM 5.1 is to difficult (or not possible), am I likely to find someone out there who wants an RM 5.1 without a tonearm and cartridge? If so, what price tag would be appropriate for it? I'm at least going to take it to my friend who has more equipment (owns a high-end audio shop) to make sure everything is in good working order, so I won't really feel bad if resell it for a little more than I bought it.