Change the server, servername, and udp stuff.
/*
 Web client sketch for IDE v1.0.1 and w5100/w5200
 Uses GET method.
 Posted October 2012 by SurferTim
 Last modified June 17, 2013
*/
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <utility/w5100.h>
// this must be unique
byte mac[] = {Â 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEC };
// change to your server
IPAddress server(1,2,3,4);
//Change to your domain name for virtual servers
char serverName[] = "1.2.3.4";
// change to your server's port
int serverPort = 80;
// Here is my udp stuff
EthernetUDP udp;
int udpPort = 8080;
IPAddress udpDest(255,255,255,255);
EthernetClient client;
int totalCount = 0;
int loopCount = 0;
char pageAdd[32];
void setup() {
 Serial.begin(115200);
 // disable w5100 SPI while starting SD
 pinMode(4,OUTPUT);
 digitalWrite(4,HIGH);
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 // Start ethernet
 Serial.println(F("Starting ethernet..."));
 if(!Ethernet.begin(mac)) Serial.println(F("failed"));
 else Serial.println(F("ok"));
 Serial.println(Ethernet.localIP());
 delay(2000);
 udp.begin(udpPort);
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 Serial.println(F("Ready"));
}
void loop()
{
 if(loopCount < 30)
 {
  // if loopCount is less than 30, just delay a second
  delay(1000);
 }
 else
 {
  // every thirty seconds this runs
  loopCount = 0;
  // Modify next line to load different page
  // or pass values to server
  sprintf(pageAdd,"/",totalCount);
  // sprintf(pageAdd,"/arduino.php?test=%u",totalCount);
  if(!getPage(server,serverPort,pageAdd)) Serial.print(F("Fail "));
  else Serial.print(F("Pass "));
  totalCount++;
  Serial.println(totalCount,DEC);
  sendUdp();
  ShowSockStatus();
 } Â
 loopCount++;
 getUdp();
}
void sendUdp() {
 udp.beginPacket(udpDest,udpPort);
 udp.write("hello");
 udp.endPacket();Â
}
void getUdp() {
 int packetSize = udp.parsePacket();
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 if(packetSize) {
  IPAddress remote = udp.remoteIP();
  Serial.println(remote);
 }
}
byte getPage(IPAddress ipBuf,int thisPort, char *page)
{
 int inChar;
 char outBuf[128];
 Serial.print(F("connecting..."));
 if(client.connect(ipBuf,thisPort) == 1)
 {
  Serial.println(F("connected"));
  sprintf(outBuf,"GET %s HTTP/1.1",page);
  client.println(outBuf);
  sprintf(outBuf,"Host: %s",serverName);
  client.println(outBuf);
  client.println(F("Connection: close\r\n"));
 }
 else
 {
  Serial.println(F("failed"));
  return 0;
 }
 // connectLoop controls the hardware fail timeout
 int connectLoop = 0;
 while(client.connected())
 {
  while(client.available())
  {
   inChar = client.read();
   Serial.write(inChar);
   // set connectLoop to zero if a packet arrives
   connectLoop = 0;
  }
  connectLoop++;
  // if more than 10000 milliseconds since the last packet
  if(connectLoop > 10000)
  {
   // then close the connection from this end.
   Serial.println();
   Serial.println(F("Timeout"));
   client.stop();
  }
  // this is a delay for the connectLoop timing
  delay(1);
 }
 Serial.println();
 Serial.println(F("disconnecting."));
 // close client end
 client.stop();
 return 1;
}
byte socketStat[MAX_SOCK_NUM];
byte destMac[6];
void ShowSockStatus()
{
 Serial.println();
 for (int i = 0; i < MAX_SOCK_NUM; i++) {
  Serial.print(F("Socket#"));
  Serial.print(i);
  uint8_t s = W5100.readSnSR(i);
  socketStat[i] = s;
  Serial.print(F(":0x"));
  if(s < 16) Serial.print(F("0"));
  Serial.print(s,HEX);
  Serial.print(F(" "));
  Serial.print(W5100.readSnPORT(i));
  Serial.print(F(" D:"));
  uint8_t dip[4];
  W5100.readSnDIPR(i, dip);
  for (int j=0; j<4; j++) {
   Serial.print(dip[j],10);
   if (j<3) Serial.print(".");
  }
  Serial.print(F("("));
  Serial.print(W5100.readSnDPORT(i));
  Serial.print(F(") "));
  W5100.readSnDHAR(i,destMac);
  for (int j=0; j<6; j++) {
   if(destMac[j] < 16) Serial.print(F("0"));
   Serial.print(destMac[j],HEX);
   if (j<5) Serial.print(":");
  }
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  Serial.println();
 }
}
edit: You will need to modify this code to wait for the UDP packet to start communicating with the server. This was just a test of the UDP and TCP protocols in the same sketch.
Have you considered using the localnet broadcast address instead of 255.255.255.255? If your localnet is 192.168.0.0/24, then the broadcast address is 192.168.0.255.
>:(
